CN102984683B - Method, device and system to achieve switching in wireless network - Google Patents

Abstract

A method, device and system for implementing handover in a wireless network, used for network anchors to obtain the access technology type of the target network, or to obtain the access technology type and policy charging rules of the target network, or to obtain The policy charging rules of the target network, and save the access technology types of the source network and the target network at the same time, or save the access technology types and policy charging rules of the source network and the target network at the same time, or save the source network and the target network at the same time Policy and charging rules of the network; so that the network anchor can select the access technology type applied to the current user according to the switching result, or the access technology type and policy charging rules. The embodiment of the present invention enables the terminal to correctly fall back to the source network when it fails to access the target network during the handover process, thereby maintaining the service continuity of the user, improving user experience, and ensuring the reliability of the service implementation process.

Description

A method, device and system for realizing handover in a wireless network

technical field

The invention relates to the technical field of wireless communication, in particular to a switching technology in a wireless network.

Background technique

In the current communication network, the PCC (Policy and Charging Control) architecture is used to control QoS (Quality of Service) and charging. During the user's business development, the PCRF (Policy and Charging Rule Function) in the PCC architecture needs to determine the corresponding policy and charging rules according to the current wireless access network of the user, so as to facilitate charging for different wireless networks. Policies and charging operations for accessing the network.

Due to the mobility of the user, the user will move between different wireless access networks, thereby changing the currently accessed wireless access network, that is, switching from the source network to the target network to conduct services. At this time, since the accessed network has changed, the PCRF needs to regenerate corresponding policy and charging rules (PCC rules) based on the target network, so as to perform accurate policy and charging operations.

At present, during the handover process, the anchor gateway (network anchor) in the network will interact with PCRF to obtain the policy and charging rules of the target network, and update the anchor with the policy and charging rules in the target network The policy and charging rules of the source network are saved in the gateway; at the same time, the RAT Type of the source network saved in the anchor gateway is updated with the RAT Type (Radio Access Technology Type) of the target network.

In the course of realizing the present invention, the inventor finds that there are at least the following problems in the prior art:

In the handover processing scheme provided by the above-mentioned prior art, if the bearer establishment in the target network fails, that is, the process of switching to the target network fails, the RAT Type and policy charging rules of the source network are no longer maintained in the anchor gateway. and other information, so that the terminal cannot correctly fall back to the source network to continue to carry out the corresponding service, resulting in the failure to guarantee the service continuity of the user, which greatly reduces the user experience.

Contents of the invention

Embodiments of the present invention provide a method, device and system for realizing handover in a wireless network, thereby improving the reliability of service realization during the handover process.

A method for implementing handover in a wireless network, comprising:

During the handover process, the network anchor obtains the access technology type of the target network, or obtains the access technology type and policy charging rules of the target network, or obtains the policy charging rules of the target network;

The network anchor saves the access technology type of the source network and the obtained access technology type of the target network at the same time, or simultaneously saves the access technology type and policy charging rules of the source network and the obtained access technology type and policy of the target network Charging rules, or simultaneously save the policy charging rules of the source network and the acquired policy charging rules of the target network;

The network anchor selects the access technology type applied to the current user according to the handover result, or the access technology type and policy charging rules, or policy charging rules.

A switching device in a network anchor, comprising:

The target parameter acquisition unit is used to acquire the access technology type of the target network, or acquire the access technology type and policy charging rules of the target network, or acquire the policy charging rules of the target network during the handover process;

The first parameter storage unit is configured to simultaneously store the access technology type of the source network and the access technology type of the target network acquired by the target parameter acquisition unit, or simultaneously store the access technology type and policy charging rules of the source network and The access technology type of the target network and the policy charging rules of the target network acquired by the target parameter acquisition unit, or simultaneously save the policy charging rules of the source network acquired by the target parameter acquisition unit and the policy accounting rules of the target network acquired fee rules;

The first parameter management unit is configured to select the access technology type applied to the current user, or the access technology type and policy charging rules, or the policy charging rules according to the switching result.

A policy charging function device, comprising:

The second parameter storage unit is configured to simultaneously store the access technology type and policy charging rules of the target network and the access technology type and policy charging rules of the source network after receiving the message carrying the handover instruction sent by the network anchor point ;

The second parameter management unit is configured to receive the notification sent by the network anchor point, and select the access technology type and policy charging rule applied to the current user according to the notification.

A system for realizing handover in a wireless network, characterized in that it includes a network anchor point and the above-mentioned policy meter functional device PCRF, the network anchor point includes the above-mentioned handover device, and during the handover process, the network anchor point requests the PCRF to acquire the target network The policy and charging rules of the target network; the PCRF generates the policy and charging rules of the target network and sends them to the network anchor.

A method for implementing handover in a wireless network, comprising:

During the handover process, the PCRF obtains the access technology type of the target network, or obtains the access technology type and policy charging rules of the target network, or obtains the policy charging rules of the target network;

The PCRF simultaneously saves the policy charging rule of the source network and the generated policy charging rule of the target network, or simultaneously saves the access technology type of the source network and the access technology type of the target network, or simultaneously saves the Access technology type and policy charging rules, as well as the access technology type and policy charging rules of the target network;

The PCRF selects the policy charging rule, or the access technology type, or the access technology type and the policy charging rule applied to the current user according to the switching result.

A policy charging function device, comprising:

The second target parameter acquisition unit is used to acquire the access technology type of the target network, or acquire the access technology type and policy charging rules of the target network, or acquire the policy charging rules of the target network during the handover process;

The third target parameter saving unit is configured to simultaneously save the policy charging rule of the source network acquired by the second target parameter acquiring unit and the generated policy charging rule of the target network, or simultaneously save the policy charging rule acquired by the second target parameter acquiring unit The access technology type of the source network and the access technology type of the target network, or simultaneously save the access technology type and policy charging rules of the source network obtained by the second target parameter acquisition unit and the access technology type and policy calculation rules of the target network fee rules;

The third parameter management unit is configured to select the policy and charging rule, or the access technology type, or the access technology type and the policy and charging rule applied to the current user in the third target parameter storage unit according to the switching result.

It can be seen from the above-mentioned technical solutions provided by the embodiments of the present invention that during the handover process, when the terminal fails to access the target network, since the access technology type of the source network has been saved, it can correctly fall back to the source network. Network, so as to maintain the service continuity of users, improve user experience, and ensure the reliability of the service realization process.

Description of drawings

FIG. 1 is a schematic diagram of a handover process in which PCRF does not participate in fallback processing provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a handover process in which PCRF participates in fallback processing provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of the handover process of Embodiment 1 provided by the embodiment of the present invention;

FIG. 4 is a schematic diagram of the handover process of Embodiment 2 provided by the embodiment of the present invention;

FIG. 5 is a schematic diagram of the handover process of Embodiment 3 provided by the embodiment of the present invention;

FIG. 6 is a schematic diagram of the handover process of Embodiment 4 provided by the embodiment of the present invention;

FIG. 7 is a schematic diagram of the handover process of Embodiment 6 provided by the embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a device provided by an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a system provided by an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a PCRF provided by an embodiment of the present invention.

Detailed ways

In the solution for implementing handover in the wireless network provided by the embodiment of the present invention, during the handover process, after the network anchor obtains the access technology type of the target network, it simultaneously saves the access technology type of the target network and the access technology of the source network type, or store the access technology type and PCC Rule (policy and charging control rules) of the target network and the access technology type and PCC Rule of the source network at the same time; The input technology type, or the access technology type and PCC Rule, so that the service can be rolled back to the source network after the handover fails.

Alternatively, in the solution for realizing handover in the wireless network provided by the embodiment of the present invention, it is also possible to save the policy charging rule of the target network at the same time after the network anchor obtains the policy charging rule (PCC Rule) of the target network during the handover process. The policy and charging rules of the source network, and the network anchor selects the policy and charging rules applied to the current user according to the handover result, so that after the handover fails, it can fall back to the source network to develop services.

The access technology type of the corresponding target network may specifically include, but is not limited to: RAT Type, or, IP-CANType (access network type based on IP connection), or, RAT Type and IP-CAN Type, etc.; The access technology type of the source network may specifically include, but is not limited to: RAT Type, or, IP-CAN Type, or, RAT Type and IP-CAN Type, and so on. The access technology type of the target network and the source network can be the same or different. For example, the access technology type of the target network is IP-CAN Type, and the access technology type of the source network is RATType and IP-CAN Type. CAN Type, etc.

Further, after the handover is successful, select the access technology type of the target network, or apply the access technology type and PCC Rule of the target network to the current user, and delete the saved access technology type of the source network, or delete the source network or, after the handover fails, select the access technology type of the source network, or apply the access technology type and PCC Rule of the source network to the current user, and delete the saved interface of the target network. input technology type, or delete the access technology type and PCC Rule of the target network.

Specifically, the network anchor point may determine that the handover is successful after determining that the IP-based connection between the terminal (current user) and the target network is successfully established. Alternatively, after it is determined that the establishment of the IP-based connection between the terminal and the target network fails, it is determined that the handover fails.

During the above processing, the corresponding network anchor point may determine that a handover is currently occurring after it has received a bearer establishment request from the target network that carries a handover instruction, and simultaneously save the access technology type of the target network and The access technology type of the source network, or save the access technology type and PCC Rule of the target network and the access technology type and PCC Rule of the source network at the same time, or save the PCC Rule of the target network and the PCCRule of the source network at the same time.

Further, if the PCC Rule of the source network is not saved in the network anchor point, after the network anchor point determines that the handover fails, it can also send a notification message carrying the access technology type of the target network to the PCRF, so that the PCRF receives the After the notification message, the PCC Rule of the source network can be generated and returned to the network anchor.

Specifically, in the embodiment of the present invention, the access technology type and PCC Rule of the target network and the access technology type and PCC Rule of the source network can also be stored in the PCRF at the same time. For example, the PCRF can receive the After carrying the handover instruction message, it is determined that a handover is currently occurring, and at the same time save the access technology type and PCC Rule of the target network and the access technology type and PCC Rule of the source network. Wherein, the handover instruction sent by the network anchor to the PCRF may be a handover instruction sent by the target network, or may be a handover instruction generated by the network anchor.

If the access technology type and PCC Rule of the target network and the access technology type and PCC Rule of the source network are saved in the PCRF at the same time, the corresponding process of saving the PCC Rule in the network anchor may include: After the PCC Rule is sent to the network anchor point, the network anchor point determines that the handover occurs according to the handover instruction contained in the received bearer establishment request, and chooses to save the access technology type of the target network and the access technology type of the source network at the same time. Alternatively, save the access technology type and PCC Rule of the target network and the access technology type and PCCRule of the source network at the same time; where, if only the access technology type of the target network and the access technology type of the source network are saved, it is also necessary to save the The PCC Rule of the source network in the network anchor is replaced by the received PCC Rule of the target network.

Since the access technology type and PCC Rule of the target network and the access technology type and PCC Rule of the source network are saved in the PCRF at the same time, any of the following processes is selected according to the handover result:

After the network anchor determines that the handover is successful, it can also notify the PCRF to select the access technology type and PCC Rule of the target network to apply to the current user, and can delete the access technology type and PCC Rule of the source network; the corresponding network anchor can specifically determine the handover After success, by carrying the information of the target network in the message sent to the PCRF, inform the PCRF to select the access technology type and PCC Rule of the target network to apply to the current user, and can delete the access technology type and PCC Rule of the source network , where the information of the target network may be the access technology type of the target network, or the access technology type of the target network and other network information.

After the network anchor determines that the handover fails, it can also notify the PCRF to select the access technology type and PCC Rule of the source network, and can delete the access technology type and PCC Rule of the target network; after the corresponding network anchor determines that the handover fails, it can specifically By carrying the information of the source network in the message sent to the PCRF, the PCRF is notified to select the access technology type and PCC Rule of the source network, and can delete the access technology type and PCC Rule of the target network, among which, the information of the source network It may be the access technology type of the source network, or it may be the access technology type of the source network and other network information.

The implementation process of the embodiment of the present invention will be further described below with reference to the accompanying drawings. In the following embodiments, the access technology type of the source network or the access technology type of the target network saved by the network anchor point, the access technology type of the source network or the access technology type of the target network sent by the network anchor point to the PCRF And the access technology type of the source network or the access technology type of the target network stored in the PCRF may be the same information or different information.

(1) The network anchor controls the handover process, and the PCRF does not participate in the fallback process after the handover fails

As shown in Figure 1, after the user UE is connected to the target network, the corresponding handover process is started, and the handover process may specifically include the following steps:

Step 11, after the network anchor point (anchor GW, anchor point gateway) receives the bearer establishment request message requesting to establish a connection, it initiates an interaction process with PCRF to obtain the PCC Rule (policy charging rule) of the target network; and, the network anchor point Click to obtain the access technology type of the target network;

Step 12, the network anchor point determines according to the handover indication carried in the connection establishment request message, it needs to save the access technology type of the source network and the access technology type of the target network at the same time, or save the access technology type of the source network and the PCC at the same time Rule and the access technology type of the target network and PCC Rule, that is, while saving the access technology type of the target network, or saving the access technology type and PCC Rule of the target network, the locally maintained source network access is not deleted Technology type, or, the access technology type and PCC Rule of the source network;

In this step 12, the PCC Rule of the source network and the PCCRule of the target network can also be saved only in the network anchor;

Step 13, executing the processing procedure for the terminal to access the target network;

During this process, the network anchor point needs to initiate the process of establishing the bearer of the target network. At this time, the downlink data in the network can still be sent to the terminal through the source network, and the corresponding charging process can continue to apply the PCC Rule of the source network, or can Apply the PCC Rule of the target network;

In step 14, the network anchor judges whether the handover is successful. The basis for judging may be whether the IP bearer between the terminal and the target network is established successfully, but is not limited to this method. If the switch to the target network is successful, the network anchor selects the access technology type of the target network and applies the PCC Rule to the current user, and can delete the locally saved access technology type of the source network, or delete the locally saved source network Access technology type and PCC Rule, and execute step 17; if the process of switching to the target network fails, the network anchor selects the access technology type and PCC Rule of the source network to apply to the current user, and can delete the locally saved target network or, delete the locally saved access technology type and PCC Rule of the target network, and perform steps 15 and 16;

In steps 15 and 16, the network anchor initiates the IP-CAN (IP-Connectivity Access Network) session modification process to the PCRF, and carries the access technology type of the source network in the message sent to the PCRF, or Carry the access technology type and network information of the source network, so as to send the corresponding information to the PCRF, so that the session between the network anchor point and the PCRF can fall back to access through the source network;

Since the session between the network anchor and the PCRF is accessed through the source network, PCRF also generates the PCC Rule corresponding to the source network according to the received information, and can return the generated PCC Rule corresponding to the source network to the network anchor point, so as to perform corresponding operations such as charging and bearer control.

Step 17, continue the subsequent handover process;

For example, if the handover is successful, the corresponding subsequent handover process may include the process of releasing resources of the source network, and if the handover fails, the corresponding subsequent handover process may include the process of the terminal returning to the source network.

(2) The network anchor controls the handover process, and the PCRF participates in the fallback process after the handover fails

As shown in Figure 2, after the user UE is connected to the target network, the corresponding handover process is started, and the handover process may specifically include the following steps:

Step 21, after the network anchor receives the bearer establishment request message requesting to establish a connection, it determines that it needs to initiate an interaction process to the PCRF;

Step 22, at the network anchor point (anchor GW, anchor point gateway), according to the handover indication Handover Indication carried in the bearer establishment request message, it is determined that an indication parameter needs to be carried in the IP-CAN session modification message sent to the PCRF to indicate that the PCRF is currently in switching state;

The corresponding indication parameter can be the handover indication Handover Indication in the received bearer establishment request message, or it can be other parameters that can realize the corresponding indication function; the indication parameter can be specifically passed through the AVP (Attribute Value Pair) carried in a manner;

Step 23: After receiving the message from the network anchor, the PCRF generates a new PCC Rule for the target network; and according to the indication parameters carried in the received message, determine to save the access technology type and PCC Rule for the target network at the same time And the access technology type and PCC Rule for the source network;

Step 24, PCRF returns the generated PCC Rule for the target network to the network anchor through the IP-CAN session modification response message;

Step 25: After receiving the PCC Rule for the target network returned by the PCRF, the network anchor determines that the access technology type and target for the source network need to be saved at the same time according to the handover indication carried in the bearer establishment request message sent by the Serving GW. The access technology type of the network, or save the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network at the same time;

Step 26, execute the processing procedure for the terminal to access the target network;

During this process, the network anchor point needs to initiate the target network bearer establishment process, so that the terminal can access the target network through the established bearer; at this time, the downlink data can still be transmitted to the terminal through the source network, and the corresponding charging operation is both You can continue to apply the PCC Rule for the source network, or you can apply the PCC Rule for the target network;

Step 27, the network anchor judges whether the handover process is successful. The specific judgment basis may be based on whether the IP bearer between the terminal and the target network is successfully established, but not limited to this method; if the corresponding IP bearer is successfully established, it indicates that it has been successful Switch to the target network. At this time, the network anchor selects the access technology type of the target network and applies the PCC Rule to the current user, and can delete the saved access technology type of the source network, or delete the saved access of the source network Technology type and PCC Rule; if the corresponding IP bearer fails to be established, it indicates that the process of handover to the target network fails. At this time, the network anchor selects the access technology type of the source network and PCC Rule to be applied to the current user, and can be deleted The access technology type of the target network, or delete the access technology type and PCC Rule of the target network;

Step 28: The network anchor initiates the IP-CAN session modification process to the PCRF. If the handover is successful, the IP-CAN session modification message carries the access technology type of the target network, or carries the access technology type and network information, so as to send the corresponding information to PCRF; if the handover fails, carry the access technology type of the source network in the IP-CAN session modification message, or carry the access technology type and network information of the source network, so as to send the corresponding The information is sent to PCRF.

Step 29: After receiving the IP-CAN session modification message sent by the network anchor, the PCRF selects the access technology type and PCC Rule applied to the current user according to the information carried in the message, and can delete the access technology type of the target network and PCCRule or the access technology type and PCC Rule of the source network, and return the IP-CAN session modification response message to the network anchor;

Specifically, if the PCRF determines that the access technology type carried in the received message is the access technology type corresponding to the source network, then select the access technology type and PCC Rule of the source network to apply to the current user, and delete the access technology type corresponding to the target network. The access technology type of the network and the PCC Rule, the session between the fallback network anchor point and the PCRF is aimed at the source network; if the PCRF determines that the access technology type carried in the received message is the access technology type corresponding to the target network, select The access technology type and PCC Rule of the target network are applied to the current user, and the access technology type and PCCRule corresponding to the source network can be deleted, and the session between the network anchor and the PCRF continues to target the target network.

Step 210, continue to execute the subsequent handover process;

For example, if the handover is successful, the corresponding subsequent handover process may include the process of releasing resources of the source network, and if the handover fails, the corresponding subsequent handover process may include the process of the terminal returning to the source network.

For ease of understanding, the specific application examples provided by the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Embodiment one

This embodiment specifically provides the corresponding network anchor point PDN GW to control the handover process, and the PCRF does not participate in the implementation scheme of the rollback after the handover fails, and the processing process in the scene of the handover success.

As shown in Figure 3, the corresponding handover process in the successful handover scenario includes:

Step 31, the terminal initiates a connection establishment process to the target network;

Specifically, the terminal may directly establish a connection with the target network, or indirectly establish a connection with the target network through the source network;

Step 32, after the Serving GW in the target network determines that the terminal initiates the establishment of the connection to the target network, it sends a bearer establishment request message to the PDN GW as the network anchor point; in the message, the handover indication is carried to indicate that the PDN GW is acquiring For the access technology type of the target network, or the access technology type and PCC Rule of the target network, continue to save the access technology type for the source network, or continue to save the access technology type and PCC Rule of the source network.

Step 33: After receiving the bearer establishment request message, the PDN GW initiates an interaction process with the PCRF, so as to obtain the PCC Rule for the target network through the interaction process;

Step 34: After receiving the PCC Rule for the target network returned by the PCRF, the PDN GW determines to save both the access technology type of the source network and the access technology type of the target network according to the handover indication carried in the bearer establishment request message, Or, save the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network at the same time. At this time, if charging, the PCC Rule of the source network can be used for charging, or the The PCC Rule of the target network is used for billing;

Step 35: The PDN GW initiates the bearer establishment process of the target network according to the received PCC Rule of the target network. After successfully completing the bearer establishment, the terminal establishes a connection with the target network and accesses the target network;

Step 36, PDN GW judges that the terminal has successfully connected to the target network, that is, the handover process is successful, then it can delete the saved access technology type of the source network, or delete the saved access technology type and PCC Rule of the source network, and select The access technology type of the target network, or select the access technology type of the target network and PCC Rule to apply to the current user, such as using the PCC Rule billing of the target network for the current user, etc.;

The basis for judging whether the handover is successful in this step may be but not limited to: determining whether the IP bearer between the terminal and the target network is successfully established. For example: during the establishment of the bearer by the PDN GW, if an Update Bearer Request message from the Serving GW is received, indicating that the bearer is established successfully in the message, it is judged that the handover is successful;

Step 37, perform subsequent switching steps.

Embodiment two

This embodiment specifically provides the corresponding network anchor point PDN GW to control the handover process, and the PCRF does not participate in the fallback after the handover fails, and the processing process in the handover failure scenario.

As shown in Figure 4, the corresponding handover processing process in the handover failure scenario includes:

Step 41, the terminal initiates a connection establishment process to the target network;

Correspondingly, the terminal can directly establish a connection with the target network, or indirectly establish a connection with the target network through the source network;

Step 42, the Serving GW in the target network determines that the terminal initiates the establishment of a connection to the target network, and then sends a bearer establishment request message to the PDN GW as the network anchor point; in the message, it carries a handover indication, indicating that the PDN GW is acquiring the target network. The access technology type of the target network, or the access technology type and PCC Rule of the target network, continue to save the access technology type for the source network, or continue to save the access technology type and PCC Rule of the source network.

Step 43: After receiving the bearer establishment request message, the PDN GW initiates an interaction process with the PCRF to obtain the corresponding PCC Rule of the target network;

Step 44: After receiving the PCC Rule of the target network returned by the PCRF, the PDN GW determines the access technology type of the source network that needs to be saved at the same time according to the handover indication carried in the bearer establishment request message received from the Serving GW. and the access technology type of the target network, or save the access technology type and PCC Rule of the network source network and the access technology type and PCC Rule of the target network at the same time; among them, if only the access technology type and For the access technology type of the target network, the received PCC Rule of the target network can be used to replace the PCC Rule of the source network saved in the PDNGW;

At this time, if the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network are saved at the same time, the PCC Rule of the source network can be used for charging when charging. The PCC Rule of the target network can also be used for billing;

Step 45, the PDN GW initiates the bearer establishment process of the target network according to the received PCC Rule of the target network, but the corresponding bearer establishment process fails, that is, the process of the terminal accessing the target network fails;

Step 46, PDN GW judges that the handover process of the terminal fails, then it can delete the access technology type of the target network, or delete the access technology type and PCC Rule of the target network, and select the access technology type of the source network, or select the source network The type of network access technology and PCC Rule applied to the current user's service process, such as billing operations, etc.;

The basis for judging the failure of the handover process may be but not limited to: the establishment of the IP bearer between the terminal and the target network fails, for example, when the PDN GW receives an Update Bearer Request message from the Serving GW during the establishment of the bearer, the message indicates that the corresponding If the bearer setup fails, or if the PDN GW does not receive a response message from the ServingGW within the predetermined time, it will confirm that the handover process has failed;

Step 47: After the PDN GW confirms that the handover fails, it needs to initiate the IP-CAN session modification process to the PCRF, and carry the access technology type for the source network in the IP-CAN session modification message sent to the PCRF, or carry the source network The type of access technology and network information, so as to make the session between PDN GW and PCRF fall back to the source network;

Step 48, the PCRF generates the corresponding PCC Rule of the source network according to the received IP-CAN session modification message, and sends it to the PDN GW through a response message, so far, the session between the PDN GW and the PCRF falls back to the source network;

Step 49, execute the subsequent handover process to complete the whole handover process.

Embodiment Three

This embodiment specifically provides that the corresponding network anchor PDN GW controls the handover process, and the PCRF also participates in the implementation scheme of the fallback after the handover fails, and the processing process in the scene of the handover success.

As shown in Figure 5, the corresponding handover process in the handover successful scenario includes:

Step 51, the terminal initiates a connection establishment process to the target network;

Specifically, the terminal may directly establish a connection with the target network, or indirectly establish a connection with the target network through the source network;

Step 52, after the Serving GW in the target network determines that the terminal initiates the establishment of the connection to the target network, it sends a bearer establishment request message to the PDN GW serving as the network anchor; The access technology type of the target network, or the access technology type and PCC Rule of the target network, and continue to save the access technology type for the source network, or continue to save the access technology type and PCC Rule of the source network.

In steps 53a, 53b, and 53c, after receiving the bearer establishment request message, the PDN GW initiates an interaction process with the PCRF to obtain the corresponding PCC Rule of the target network;

Step 53a, the PDN GW carries an indication parameter in the IP-CAN session modification message sent to the PCRF according to the handover indication carried in the received bearer establishment request message, to indicate that the PCRF is currently in the handover state; the indication parameter can be directly The received Handover Indication can also be other parameters with similar functions; the IP-CAN session modification message sent to the PCRF also carries the access technology type of the target network, or carries the access technology type of the target network and target network information;

Step 53b, PCRF generates the PCC Rule of the corresponding target network according to the information carried in the IP-CAN session modification message received from the PDN GW, and determines the access technology type of the target network that needs to be saved according to the received indication parameters and PCC Rule, as well as the access technology type and PCC Rule of the source network;

Step 53c, the PCRF returns the corresponding IP-CAN session modification response message to the PDN GW, and the message carries the generated PCC Rule of the target network;

Step 54: After receiving the PCC Rule of the corresponding target network, the PDN GW determines the target network that needs to save the access technology type of the source network at the same time according to the handover indication carried in the received bearer establishment request message sent by the Serving GW access technology type, or save the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network at the same time;

At this time, if the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network are saved at the same time, in the charging process, either the source network PCC Rule can be used for charging, or the target network PCC Rule can be used for charging. Network PCC Rule for billing;

Step 55: The PDN GW initiates the bearer establishment process of the target network according to the received PCC Rule of the target network. After the bearer establishment is completed, the terminal establishes a connection with the target network, that is, the terminal successfully switches to the target network;

Step 56: After the PDN GW judges that the handover is successful, it can delete the corresponding access technology type of the source network, or delete the access technology type and PCC Rule of the source network, and select the access technology type of the target network, or select the target network The type of network access technology and PCC Rule applied to the current user service, such as using the PCC Rule of the target network for billing, etc.;

The basis for judging the success of the handover may be but not limited to: determining that the IP bearer between the terminal and the target network is successfully established. For example, the PDN GW receives an Update Bearer Request message from the Serving GW during the establishment of the bearer, indicating that the bearer is successfully established. Then it is determined that the switching is successful;

Step 57, after the PDN GW determines that the handover is successful, it also sends an IP-CAN session modification message to the PCRF, and carries the access technology type of the target network in the message, or carries the access technology type and network information of the target network;

Step 58: After receiving the IP-CAN session modification message sent by the PDN GW, the PCRF selects the access technology type and PCC Rule of the target network to apply to the current user, and can delete the access technology type and PCC Rule of the source network, and Return IP-CAN session modification response message to PDNGW;

In this step, the PCRF may not need to re-determine to generate the corresponding PCC Rule of the target network, or may not need to carry the corresponding PCC Rule of the target network in the response message;

Step 59, perform subsequent switching steps.

Embodiment Four

This embodiment specifically provides that the corresponding network anchor PDN GW controls the handover process, and the PCRF also participates in the implementation scheme of the fallback after the handover fails, and the processing process in the handover failure scenario.

As shown in Figure 6, the corresponding handover process in the handover successful scenario includes:

Step 61, the terminal initiates a connection establishment process to the target network;

Specifically, the terminal may directly establish a connection with the target network, or indirectly establish a connection with the target network through the source network;

Step 62, after the Serving GW in the target network determines that the terminal initiates the establishment of the connection to the target network, it sends a bearer establishment request message to the PDN GW serving as the network anchor;

In steps 63a, 63b, and 63c, after the PDN GW receives the bearer establishment request message, it initiates an interaction process with the PCRF to obtain the PCC Rule of the corresponding target network; in the message, the handover indication is carried to indicate that the PDN When the GW obtains the access technology type for the target network, or obtains the access technology type and PCC Rule for the target network, it continues to save the access technology type for the source network, or continues to save the access technology type for the source network and PCC Rule.

Step 63a: According to the handover indication carried in the received bearer establishment request message, the PDN GW carries an indication parameter in the IP-CAN session modification message sent to the PCRF to indicate that the PCRF is currently in the handover state; the indication parameter can be directly The received Handover Indication can also be other parameters with similar functions; the IP-CAN session modification message sent to the PCRF also carries the target network access technology type, or carries the target network access technology type and target network information;

Step 63b, PCRF generates the PCC Rule of the corresponding target network according to the information carried in the IP-CAN session modification message received from the PDN GW, and determines the access technology type of the target network that needs to be saved according to the received indication parameters and PCC Rule and the access technology type and PCC Rule of the source network;

Step 63c, the PCRF returns the corresponding IP-CAN session modification response message to the PDN GW, and the message carries the generated PCC Rule of the target network;

Step 64: After receiving the PCC Rule of the corresponding target network, the PDN GW determines that the access technology type of the source network and the target network need to be saved at the same time according to the handover indication carried in the received bearer establishment request message sent by the Serving GW access technology type, or save the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network at the same time;

At this time, if the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network are saved at the same time, in the charging process, either the PCC Rule of the source network can be used for charging, or the PCC Rule of the target network can be used. The PCC Rule of the target network is used for billing;

Step 65: After receiving the PCC Rule of the target network, the PDN GW initiates the bearer establishment process of the target network according to the PCC Rule of the target network, but the corresponding bearer establishment process fails, that is, the terminal fails to access the target network, resulting in handover failure;

Step 66: After the PDN GW judges that the handover fails, it can delete the access technology type of the target network, or delete the access technology type and PCC Rule of the target network, and select the access technology type of the source network, or select the access technology type of the source network The access technology type and PCC Rule are applied to the current user, for example, the PCC Rule of the source network is used for billing, etc.;

The basis for judging the corresponding handover failure may be but not limited to: determine that the establishment of the IP bearer between the terminal and the target network fails, for example, the PDN GW receives an Update Bearer Request message from the Serving GW during the establishment of the bearer indicating that the bearer establishment failed, or , PDN GW does not receive a response message from Serving GW within the predetermined time, then it is determined that the handover fails;

Step 67: After the PDN GW determines that the handover fails, it needs to send an IP-CAN session modification message to the PCRF, in which the message carries the access technology type for the source network, or carries the access technology type and network information of the source network.

Step 68, after the PCRF receives the IP-CAN session modification message, it determines to select the access technology type of the source network and PCC Rule to apply to the current user according to the information carried in the message, and can delete the access technology type of the target network and PCC Rule, and return the IP-CAN session modification response message to the PDN GW. The session between the PDN GW and the PCRF falls back to the source network;

In this step, the PCRF may not need to make a new decision to generate the corresponding PCC Rule of the source network, or may not need to carry the PCC Rule of the source network in the IP-CAN session modification response message;

Step 69, perform subsequent switching steps.

In the above process, the corresponding access technology type of the source network and the access technology type of the target network may be the same information or different information. For example, when the terminal accesses the network from a non-3GPP network, the corresponding The access technology type can be but not limited to IP-CAN Type. When the terminal accesses the network from 3GPP, the corresponding access technology type can be but not limited to RAT Type and IP-CAN Type, etc.

It can be seen from the above embodiments that during the handover process, if the terminal fails to access the target network, it can correctly fall back to the source network to continue the service, effectively ensuring the continuity of the service.

It should be noted that, in the first to fourth embodiments above, before the PDN GW performs Path Switch (path switching), the step of interacting with the PCRF is an optional step.

Embodiment five

In this embodiment, the processing process is similar to that of Embodiment 1 to Embodiment 4 above, and the difference is that: in the processing process of Embodiment 1 to Embodiment 4 above, the network anchor needs to save the access technology type of the target network at the same time and the access technology type of the source network, or save the access technology type and PCC Rule of the target network and the access technology type and PCC Rule of the source network at the same time; and in the fifth embodiment, when the network anchor obtains the target network After the PCC Rule, the PCC Rule of the target network and the PCC Rule of the source network are saved at the same time; and the PCC Rule applied to the current user is selected by the network anchor according to the switching result, so that it can smoothly fall back to the source after the switching fails conduct business on the network.

Specifically, the network anchor point may determine that the handover is successful after determining that the IP-based connection between the terminal (current user) and the target network is successfully established. Alternatively, after it is determined that the establishment of the IP-based connection between the terminal and the target network fails, it is determined that the handover fails.

In the above process, the corresponding network anchor can determine that a handover is currently occurring after it has received the bearer establishment request from the target network to carry a handover instruction, and save the PCC Rule of the target network and the source network at the same time. The PCC Rule.

That is to say, in each of the above-mentioned embodiments, the access technology type of the source network and the technology type of the target network, or the access technology type of the source network and the PCC Rule And the access technology type and PCC Rule of the target network, in the application scenario of the fifth embodiment, both are adjusted to at least one of PDN GW or PCRF. The PCC Rule of the target network and the PCC Rule of the target network. That is: before the PDN GW switches the user plane path to the target network, at least one of the PDN GW or the PCRF saves the PCC Rule of the source network and the PCC Rule of the target network at the same time; if it is determined that the handover is successful, both the PDNGW or the PCRF At least one of the PCC Rules of the source network is deleted, and the PCC Rule of the target network is selected to apply to the current user; PCC Rule applies to the current user.

Embodiment six

In the sixth embodiment, the corresponding network anchor point PCRF control switching process is specifically provided. At this time, based on Proxy MIP (Mobile IP) between ServingGW and PDN GW, that is, the communication method of proxy mobile IP, the corresponding Serving GW can have the function of BBERF.

As shown in Figure 7, the corresponding handover process in the handover successful scenario includes:

Step 71, the terminal initiates a connection establishment process to the target network, and starts the handover process;

Specifically, the terminal may directly establish a connection with the target network, or indirectly establish a connection with the target network through the source network;

In steps 72a, 72b, and 72c, the Serving GW initiates the gateway control session establishment interaction process with the PCRF; in the message transmitted during the gateway control session establishment interaction process, a new AVP may carry an indication, such as: handoverIndication, indicating that the PCRF is currently to switch. PCRF can determine the handover process based on received instructions or its own judgment, and after generating the PCC Rule of the target network, simultaneously save the PCC Rule of the source network and the PCC Rule of the target network, or save the access technology of the source network at the same time type and the access technology type of the target network, or save the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network at the same time, and the corresponding processing may specifically include:

Step 72a, the Serving GW sends a gateway control session establishment request message to the PCRF, in which the AVP may carry an indication, such as: handover Indication, to the PCRF to indicate that the PCRF is currently switching;

Step 72b, PCRF determines that it is currently a handover process according to the received instruction or its own judgment, and simultaneously saves the PCC Rule of the source network and the PCC Rule of the target network, or simultaneously saves the access technology type of the source network and the access technology type of the target network. input technology type, or save the access technology type and PCC Rule of the source network and the access technology type and PCC Rule of the target network at the same time;

Step 72c, complete the rest of the gateway control session establishment process. In this establishment process, after the Serving GW completes the application enhancement of the received rules—such as the application of the rules to establish the bearer—the PCRF rules can be notified by a response message The application result; the Serving GW can also notify the PCRF rule application result by initiating the gateway control session modification process.

Afterwards, if the handover is successful, then execute step 74 and steps 75a, 75b, 75c, if the handover fails, then execute step 73;

Step 73, if the PCRF determines that the application rule fails, such as: all bearers of the Serving GW application rule fail to be established, then the PCRF deletes the saved PCC Rule of the target network, or deletes the saved access technology type of the target network, or deletes the saved target network Network PCC Rule and access technology type. And apply the PCC Rule of the source network, or apply the access technology type of the source network, or apply the PCC Rule and the access technology type of the source network to the current user, and perform step 76.

Step 74, the terminal successfully accesses the target network, and executes steps 75a, 75b, and 75c;

In steps 75a, 75b, and 75c, the PDN GW initiates the IP-CAN session modification process to the PCRF. In the IP-CAN session modification request message sent, the AVP may carry an indication to the PCRF to indicate that the PCRF handover is successful; or, the PCRF may also The reception of the IP-CAN session modification request message sent by the PDN GW is regarded as an indication of a successful handover; after determining that the handover is successful, the PCRF deletes the stored PCC Rule of the source network, or deletes the stored access technology type of the source network, or Delete the saved PCC Rule and access technology type of the source network; and apply the PCC Rule of the target network, or apply the access technology type of the target network, or apply the PCC Rule and access technology type of the target network to the current user, correspondingly Specifically, the processing process may include:

Step 75a: The PDN GW initiates the IP-CAN session modification process to the PCRF. In the IP-CAN session modification request message sent, the AVP may carry an indication to the PCRF to indicate that the PCRF handover is successful, or the PCRF may also receive the PDN The IP-CAN session modification request message sent by the GW is regarded as an indication of a successful handover;

Step 75b, after the PCRF determines that the current handover has been successful, delete the stored PCC Rule of the source network, or delete the stored source network access technology type, or delete the stored source network PCC Rule and access technology type; and apply PCC Rule of the target network, or apply the access technology type of the target network, or apply the PCCRule and access technology type of the target network to the current user;

Step 75c, complete the remaining IP-CAN session modification process;

Step 76, execute subsequent switching steps.

The embodiment of the present invention also provides a switching device in a network anchor point, its specific implementation structure is shown in Figure 7, and may specifically include:

(1) A target parameter acquisition unit, configured to acquire the access technology type of the target network, or acquire the access technology type and policy charging rules of the target network, or acquire the policy charging rules of the target network during the handover process;

(2) The first parameter storage unit is configured to simultaneously store the access technology type of the source network and the access technology type of the target network acquired by the target parameter acquisition unit, or simultaneously store the access technology type and the policy calculation type of the source network charging rules and the access technology type of the target network and the policy charging rules of the target network obtained by the target parameter acquisition unit, or simultaneously save the policy charging rules of the source network and the policy charging rules of the target network acquired by the target parameter acquisition unit ;

(3) A first parameter management unit, configured to select an access technology type applied to the current user, or an access technology type and a policy charging rule, or a policy charging rule according to the switching result;

After determining that the handover is successful, the first parameter management unit may specifically complete corresponding processing through the following units, and the corresponding units may specifically include:

The first parameter selection unit is configured to select the access technology type of the target network after determining that the handover is successful (applicable to the case where only the access technology type of the source network and the access technology type of the target network are saved at the same time), or select The access technology type and policy and charging rules of the target network (applicable to the situation where the access technology type and policy and charging rules of the source network and the access technology type and policy and charging rules of the target network are saved at the same time), or select the target The policy and charging rules of the network are applied to the current user;

The first deletion operation unit is configured to delete the access technology type of the source network, or delete the access technology type and policy charging rules of the source network, or delete the policy charging rules of the source network after determining that the handover is successful.

After determining that the handover fails, the first parameter management unit may specifically complete corresponding processing through the following units, and the corresponding units may specifically include:

The second parameter selection unit is configured to select the access technology type of the source network, or select the access technology type and policy charging rules of the source network, or select the policy charging rules of the source network to be applied to the current user;

The second deletion operation unit is configured to delete the access technology type of the target network, or delete the access technology type and policy charging rules of the target network, or delete the policy charging rules of the target network after determining that the handover fails.

Optionally, the apparatus may further include a first handover identification unit, configured to notify the first parameter storage unit to simultaneously store the source network address after determining that a handover occurs according to the handover indication carried in the received bearer establishment request message. The policy and charging rules of the target network and the policy and charging rules of the target network acquired by the target parameter acquisition unit, or simultaneously save the access technology type of the source network and the access technology type of the target network acquired by the target parameter acquisition unit, Alternatively, the access technology type and policy charging rules of the source network and the access technology type and policy charging rules of the target network acquired by the target parameter acquisition unit are saved at the same time.

Further, the above-mentioned first parameter management unit may also include:

The first notification unit is configured to send a notification message carrying the access technology type of the target network to the PCRF after determining that the handover fails, so as to notify the PCRF to return the policy and charging rules of the source network;

or,

The second notification unit is used to notify the PCRF to delete the access technology type and policy charging rules of the source network after determining that the handover is successful;

or,

The third notification unit is configured to notify the PCRF to delete the access technology type and the policy charging rule of the target network after determining that the handover fails.

Wherein, the first parameter management unit may also include a second notification unit and a third notification unit, so as to complete corresponding processing after the handover succeeds or fails, respectively.

The access technology type of the corresponding target network may specifically include, but is not limited to: RAT Type, or, IP-CAN Type, or, RAT Type and IP-CAN Type, etc.; the specific access technology type of the corresponding source network may be but not limited to: It is not limited to include: RAT Type, or, IP-CAN Type, or, RAT Type and IP-CAN Type, etc. The access technology type of the target network can be the same as or different from that of the source network. For example, if the target network is a non-3GPP access network, the access technology type of the target network can be but not limited to IP- CAN Type, if the source network is a 3GPP access network, the access technology type of the source network can be but not limited to RAT Type and IP-CAN Type, etc.

The embodiment of the present invention also provides a system for implementing handover in a wireless network. Its specific implementation structure is shown in FIG. 8 , including a network anchor point and a policy charging function device (PCRF). , during the handover process, the network anchor requests the PCRF to acquire the policy and charging rules of the target network; the PCRF generates the policy and charging rules of the target network and sends them to the network anchor.

Further, the specific implementation structure of the corresponding policy billing power equipment is still shown in Figure 8, which may specifically include:

The second parameter storage unit is configured to simultaneously store the access technology type and policy charging rules of the target network and the access technology type and policy charging rules of the source network after receiving the message carrying the handover instruction sent by the network anchor point ;

The second parameter management unit is configured to receive the notification sent by the network anchor point, and select the access technology type and policy charging rule applied to the current user according to the notification.

Wherein, the corresponding second parameter management unit may specifically include at least one of the following:

The first selection unit is configured to carry the information of the target network in the session modification message sent by the network anchor, such as carrying the access technology type of the target network, or the access technology type and network information of the target network, etc. etc., it is determined that the handover is successful, and the access technology type and policy charging rules of the target network stored in the second parameter storage unit are selected to be applied to the current user; further, at this time, the second parameter management unit can also delete the The access technology type and policy charging rules of the source network stored in the second parameter storage unit;

The second selection unit is used to carry the source network information in the session modification message sent by the network anchor, such as carrying the access technology type of the target network, or the access technology type and network information of the target network, etc. etc., it is determined that the handover fails, and the access technology type and policy charging rules of the source network stored in the second parameter storage unit are selected to be applied to the current user; further, at this time, the second parameter management unit can also delete the The access technology type and policy charging rules of the target network stored in the second parameter storage unit.

The embodiment of the present invention also provides another policy charging function device, that is, PCRF, its specific implementation structure is shown in Figure 10, and may include the following units:

The second target parameter acquisition unit is used to acquire the access technology type of the target network, or acquire the access technology type and policy charging rules of the target network, or acquire the policy charging rules of the target network during the handover process;

The third target parameter storage unit is configured to simultaneously store the policy charging rules of the source network and the policy charging rules of the target network acquired by the second target parameter acquisition unit, or simultaneously store the access information of the source network acquired by the second target parameter acquisition unit. The input technology type and the access technology type of the target network, or simultaneously save the access technology type and policy charging rules of the source network obtained by the second target parameter acquisition unit and the access technology type and policy charging rules of the target network;

The third parameter management unit is configured to select the policy charging rule, or the access technology type, or the access technology type and the policy charging rule applied to the current user in the third target parameter storage unit according to the switching result.

The above-mentioned third parameter management unit may specifically include a third parameter selection unit and a third parameter deletion unit, wherein:

The third parameter selection unit is configured to select the policy charging rule of the target network, or select the access technology type of the target network, or select the access technology type and the policy charging rule of the target network after determining that the handover is successful, which is applied to Current user;

The third parameter deletion unit is configured to delete the policy charging rule of the source network, or delete the access technology type of the source network, or delete the access technology type and the policy charging rule of the source network after determining that the handover is successful.

Correspondingly, the manner of determining the success of the handover may be, but not limited to: determine the success of the handover according to the session establishment request message sent by the network anchor, that is, as long as the session establishment request message is received, the handover is considered successful, or, it may also be determined according to the session establishment request message The handover success indication carried in the message determines that the handover result is handover success.

Alternatively, the third parameter management unit may specifically include a fourth parameter selection unit and a fourth parameter deletion unit, wherein:

The fourth parameter selection unit is used to select the policy charging rule of the source network, or select the access technology type of the source network, or select the access technology type and the policy charging rule of the source network after determining that the handover fails. Current user;

The fourth parameter deletion unit is configured to delete the policy charging rule of the target network, or the access technology type of the target network, or delete the access technology type and policy charging rule of the target network after it is determined that the handover fails.

Correspondingly, the manner of determining the handover failure may be but not limited to: when the application result of the policies and rules reported by the bearer binding and event reporting functional entity BBERF is failure, then determine that the handover result is handover failure. Specifically, BBERF reports the application results of policies and rules through the session establishment response message, or BBERF reports the application results of policies and rules through the session modification process.

Optionally, the device may also include a second handover identification unit, configured to determine that the session establishment request message sent by the target network BBERF is received, or the handover instruction carried in the session establishment request message sent by the target network BBERF Afterwards, notify the third target parameter storage unit to store the policy charging rules of the source network and the generated policy charging rules of the target network at the same time, or store the access technology type of the source network and the access technology type of the target network at the same time , or, simultaneously save the access technology type and the policy charging rule of the source network and the acquired access technology type of the target network and the generated policy charging rule.

To sum up, the processing mechanism provided by the embodiment of the present invention can ensure that during the handover process, after the terminal fails to access the target network, it can correctly fall back to the source network to continue the service, thereby effectively maintaining the service continuity of the user. Improve the user's application experience.

Those of ordinary skill in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be completed by instructing related hardware through a program. The program can be stored in a computer-readable storage medium, and the program includes the above-mentioned steps when executed. Steps in the examples. The corresponding storage medium may be a read-only memory, a magnetic disk or an optical disk, and the like.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. A method for realizing switching in a wireless network, characterized in that, comprising: During the handover process, the packet data network gateway PDN GW obtains the access technology type of the target network, or obtains the access technology type and policy charging rules of the target network, or obtains the policy charging rules of the target network; The PDN GW simultaneously stores the access technology type of the source network and the acquired access technology type of the target network, or simultaneously stores the access technology type and policy charging rules of the source network and the acquired access technology of the target network Type and policy charging rule, or save the policy charging rule of the source network and the acquired policy charging rule of the target network at the same time; The PDN GW selects the access technology type applied to the current user according to the handover result, or the access technology type and policy charging rules, or policy charging rules; Said options include: If the handover is successful, select the access technology type of the target network, or select the access technology type and policy charging rules of the target network, or select the policy charging rules of the target network, and apply to the current user; and delete the source network or, delete the access technology type and policy charging rule of the source network, or delete the policy charging rule of the source network, or If the switching fails, select the access technology type of the source network, select the access technology type and policy charging rules of the source network, or select the policy charging rules of the source network, and apply to the current user; and delete the target network Access technology type, delete the access technology type and policy charging rule of the target network, or delete the policy charging rule of the target network. 2. The method according to claim 1, wherein the access technology type of the target network comprises: a radio access technology type RAT Type, or, based on an IP-connected access network type IP-CAN Type, Or, RATType and IP-CAN Type; the access technology type of the source network includes: RAT Type, or, IP-CANType, or, RAT Type and IP-CAN Type. 3. The method according to claim 1, characterized in that the method further comprises: After the PDN GW determines that the IP-based connection between the terminal and the target network is successfully established, it determines that the handover is successful. 4. The method according to claim 1, characterized in that the method further comprises: After the PDN GW determines that the establishment of the IP-based connection between the terminal and the target network fails, it determines that the handover fails. 5. The method according to any one of claims 1 to 4, wherein the simultaneous saving comprises: After the PDN GW determines that the bearer establishment request sent by the target network carries a handover instruction, it simultaneously saves the access technology type of the source network and the acquired access technology type of the target network, or simultaneously saves the The access technology type and policy charging rule and the acquired access technology type and policy charging rule of the target network, or simultaneously save the policy charging rule of the source network and the acquired policy charging rule of the target network. 6. The method according to claim 5, wherein after determining that the handover fails, if the PDN GW confirms that the bearer establishment request sent by the target network carries a handover instruction, it simultaneously saves the information of the source network The access technology type and the obtained access technology type of the target network, the method further includes: The PDN GW sends a notification message carrying the access technology type of the target network to the policy and charging functional entity PCRF, so that the PCRF returns the generated policy and charging rules of the source network to the PDN GW after receiving the notification message. 7. A switching device in a packet data network gateway PDN GW, characterized in that, comprising: The target parameter acquisition unit is used to acquire the access technology type of the target network, or acquire the access technology type and policy charging rules of the target network, or acquire the policy charging rules of the target network during the handover process; The first parameter storage unit is configured to simultaneously store the access technology type of the source network and the access technology type of the target network acquired by the target parameter acquisition unit, or simultaneously store the access technology type and policy charging rules of the source network and The access technology type of the target network and the policy charging rules of the target network acquired by the target parameter acquisition unit, or simultaneously save the policy charging rules of the source network and the acquired policy charging rules of the target network; The first parameter management unit is configured to select the access technology type applied to the current user according to the switching result, or the access technology type and the policy charging rule, or the policy charging rule; The first parameter management unit includes: The first parameter selection unit is configured to select the access technology type of the target network, or the access technology type and policy charging rules of the target network, or apply the policy charging rules of the target network to the current user after determining that the handover is successful; and The first deletion operation unit is configured to delete the access technology type of the source network, or delete the access technology type and the policy charging rule of the source network, or delete the policy charging rule of the source network after determining that the handover is successful; Or the first parameter management unit includes: The second parameter selection unit is configured to select the access technology type of the source network, or select the access technology type and policy charging rules of the source network, or select the policy charging rules of the source network after determining that the handover fails, and is applied to current user; and The second deletion operation unit is configured to delete the access technology type of the target network, or delete the access technology type and policy charging rules of the target network, or delete the policy charging rules of the target network after determining that the handover fails. 8. The device according to claim 7, further comprising: The first handover identification unit is configured to notify the first parameter storage unit to simultaneously store the access technology type of the source network and the acquisition of the target parameter after determining that a handover occurs according to the handover instruction carried in the received bearer establishment request message The access technology type of the target network acquired by the unit, or simultaneously save the access technology type and policy charging rules of the source network and the access technology type and policy charging rules of the target network acquired by the target parameter acquisition unit, or , saving the policy and charging rules of the source network and the policy and charging rules of the target network acquired by the target parameter acquisition unit at the same time. 9. The device according to claim 7, wherein the first parameter management unit further comprises: The first notification unit is configured to send a notification message carrying the access technology type of the target network to the PCRF after determining that the handover fails, so as to notify the PCRF to return the policy and charging rules of the source network; or, The second notification unit is configured to notify the PCRF to delete the access technology type and policy charging rules of the source network after determining that the handover is successful; or, The third notification unit is configured to notify the PCRF to delete the access technology type and the policy charging rule of the target network after determining that the handover fails. 10. A system for realizing handover in a wireless network, characterized in that it includes a packet data network gateway PDN GW and a policy meter function device PCRF, and the PDN GW includes the handover device described in any one of claims 7 to 9, in During the handover process, the PDN GW requests the PCRF to obtain the policy and charging rules of the target network; the PCRF generates the policy and charging rules of the target network and sends them to the PDN GW.