CN102177748B

CN102177748B - Method for network handover, terminal, gateway and network system thereof

Info

Publication number: CN102177748B
Application number: CN200980150126.4A
Authority: CN
Inventors: 刘清顺
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2009-01-08
Filing date: 2009-01-08
Publication date: 2013-03-20
Anticipated expiration: 2029-01-08
Also published as: CN102177748A; WO2010078725A1

Abstract

The embodiments in the present invention disclose a method, user equipment (UE), gateway and network system for network handover. The method comprises: the long term evolution (LTE) network side sends the UE a message to indicate that the UE has been allowed to be registered with the evolved high rate packet data (eHRPD) network; when the UE has been registered with the eHRPD network via the eHRPD air interface, the eHRPD network side establishes a proxy mobile IP tunnel through which the UE is handed over to the eHRPD network. The UE comprises a registration module and a trigger module. The gateway comprises a receiving module and a tunnel establishment module. The system comprises a UE, a base station and an HRPD serving gateway (HSGW). The embodiments in the present invention can decrease the handover interrupt time and reduce the complexity of the network and the UE.

Description

Network switching method, terminal, gateway and network system

Technical Field

The present invention relates to the field of mobile communications technologies, and in particular, to a network switching method, a terminal, a gateway, and a network system.

Background

LTE (Long Term Evolution) is an Evolution of 3GPP (Third generation partnership Project) that improves and enhances 3G over-the-air access technology, using orthogonal frequency division multiplexing and multiple-input multiple-output as the only standards for its wireless network Evolution. In an LTE network, Serving gateways and PDN gateways (packet data network gateways, P-GWs) are evolved gateways and are responsible for forwarding data packets, and an MME (Mobility management entity) is a signaling control entity and is responsible for functions such as authentication and Mobility management. The evolved network does not provide the voice function of the traditional circuit switching, only provides a high-speed data bearing service, and can also support the intercommunication with a third generation wireless data network and a second point fifth generation wireless data network of 3 GPP.

HRPD (High Rate Packet Data) is a third generation Data wireless communication system defined by 3GPP2 (third generation Partnership Project 2), does not provide traditional circuit switched voice functionality, and provides only High Rate Data bearer services. In AN HRPD Network, AN Access Network (AN) entity is a Network element, which is equivalent to a base station and a base station controller, and is responsible for functions such as data modulation and demodulation and handover. The PCF (Packet control function) entity is responsible for data forwarding and Packet data session state maintenance. eHRPD (evolved High Rate Packet Data) is an evolution of an HRPD network for interoperation with LTE, that is, an HRPD network needs to be evolved to eHRPD first for interoperation with LTE.

When a UE (User Equipment, also called a terminal) is handed over from an LTE network to an eHRPD network, the prior art generally uses two ways to complete the handover. The first mode is non-optimized switching, no interface exists between an LTE wireless network and an eHRPD wireless network in a non-optimized switching network architecture, the LTE and the eHRPD access a unified EPC (Evolved Packet Core), and an access anchor point is a PDN Gateway. When the UE is handed over between LTE and eHRPD, the UE performs eHRPD session negotiation, PPP (Point-to-Point Protocol) negotiation, and EAP-AKA (extensible Authentication Protocol-Authentication and Key Agreement) Authentication in the eHRPD network, and then initiates proxy mobile IP tunnel establishment to the PDN Gateway by the HSGW (HRPD Serving Gateway), and the PDN Gateway releases the proxy mobile IP tunnel between the PDN Gateway and the S-GW (Serving Gateway), thereby completing the handover from the LTE network to the eHRPD network.

The second mode is optimized handover, in which two interfaces are added between an LTE Network and an eHRPD Network, one interface is an S101 interface between an MME and an eAN (Access Network), and is essentially a tunnel, which forwards signaling and data between the UE and a target Network, and assists the UE to perform pre-registration in the target Network or handover from a source Network to the target Network; the other interface is an S103 interface between the Serving Gateway and the HSGW, and is used for forwarding data retained by the 3GPP evolved network to the eHRPD network, and then sending the data to the UE through the eHRPD network. When the UE resides in the LTE network, pre-registration is carried out in advance through the LTE network and the S101 tunnel, and eHRPD session negotiation, PPP negotiation and EAP-AKA authentication are carried out with the target eHRPD network; when the switching condition from LTE to eHRPD is met, the switching message is sent to the target eHRPD through the LTE and S101 tunnels, and after the target eHRPD distributes wireless resources, the UE leaves the LTE again to access the target eHRPD, so that the switching time is greatly shortened. Optionally, the lossless transmission problem of the data can be solved by using the S103 tunnel, and the packet loss rate in the transmission process is reduced.

In the process of implementing the invention, the inventor finds that the prior art has at least the following disadvantages:

in the first mode, when the UE decides to initiate a handover from LTE to eHRPD, i.e. leaves the source LTE network, and performs eHRPD session negotiation, PPP negotiation, EAP-AKA authentication, and other procedures in the target eHRPD network, as it usually takes several seconds to perform these procedures, the handover interruption time is long, and the user experience is affected. Although the second method greatly reduces the service interruption time from LTE to eHRPD handover, two interfaces need to be added between LTE and eHRPD networks, which increases the complexity of the networks, and the protocol stack of the UE needs to be modified to enable the UE to send an eHRPD message through LTE, thereby increasing the complexity of the UE.

Disclosure of Invention

The embodiment of the invention provides a network switching method, a terminal, a gateway and a network system, which can shorten the switching time of UE from an LTE network to an eHRPD network and reduce the complexity of the network and the UE.

The technical scheme is as follows:

a network switching method is applied to a Long Term Evolution (LTE) network and an evolved high rate packet data (eHRPD) network, and comprises the following steps:

the LTE network side sends a message to a terminal to indicate that the terminal is allowed to register the eHRPD network;

when the terminal completes the registration to the eHRPD network through an eHRPD air interface and decides to switch to the eHRPD network, the eHRPD network side establishes a proxy mobile IP tunnel from a high-rate packet data service gateway (HSGW) to a packet data network gateway (P-GW), and the proxy mobile IP tunnel completes the switching from the terminal to the eHRPD network.

A terminal, comprising:

the registration module is used for registering the eHRPD network through an evolved high-rate grouped data eHRPD air interface according to the indication of the LTE network when the terminal resides in the long term evolution LTE network;

and the triggering module is used for establishing an air interface connection after the registration module finishes registration and the terminal determines to be switched to the eHRPD network, triggering the eHRPD network to establish a proxy mobile IP tunnel from a high-rate packet data service gateway (HSGW) to a packet data network gateway (P-GW), and finishing the switching of the terminal from the LTE network to the eHRPD network through the proxy mobile IP tunnel.

A gateway in an evolved high rate packet data, eHRPD, network, the gateway comprising:

a receiving module, configured to receive a request message sent by a terminal in a registration process of an eHRPD network;

a tunnel establishing module, configured to determine whether the content of the attach type field carried in the request message received by the receiving module is registration, if so, not to establish a proxy mobile IP tunnel to a packet data network gateway P-GW in the registration process, and when the terminal completes registration from the LTE network to the eHRPD network and determines to switch to the eHRPD network, establish a proxy mobile IP tunnel to the P-GW, and complete the switch from the terminal to the eHRPD network through the proxy mobile IP tunnel.

A network system, comprising:

the terminal is used for registering the eHRPD network through an eHRPD air interface according to an instruction from the LTE network when the terminal is resident in a Long Term Evolution (LTE) network, establishing air interface connection with the eHRPD network, and triggering the eHRPD network to establish a proxy mobile IP tunnel from a high-rate packet data service gateway (HSGW) to a packet data network gateway (P-GW);

the base station is positioned in the LTE network and used for sending a message to the terminal and indicating that the terminal is allowed to register in the eHRPD network;

and the high-rate packet data service gateway (HSGW) is positioned in the eHRPD network and is used for establishing a proxy mobile IP tunnel to a packet data network gateway (P-GW) when the terminal completes the registration from the LTE network to the eHRPD network, and the proxy mobile IP tunnel completes the handover of the terminal from the LTE network to the eHRPD network.

The embodiment of the invention registers the eHRPD network through the eHRPD air interface in the LTE network before the UE decides to initiate the switching from the LTE to the eHRPD, thereby greatly reducing the switching interruption time, improving the user experience, reducing the network complexity without increasing an interface between the LTE network and the eHRPD network, and reducing the UE complexity without modifying the protocol stack of the UE.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is an architecture diagram of an LTE network and an eHRPD network provided by an embodiment of the present invention;

fig. 2 is a flowchart of a network handover method according to an embodiment of the present invention;

fig. 3 is a flowchart of registration in a network handover method according to an embodiment of the present invention;

fig. 4 is a handover flowchart in a network handover method according to an embodiment of the present invention;

fig. 5 is a flow chart of an air interface session keep-alive according to an embodiment of the present invention;

fig. 6 is a flowchart of subnet change processing provided by an embodiment of the present invention;

fig. 7 is another handover flow chart provided by the embodiment of the present invention;

fig. 8 is a flowchart of another network handover method according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of a base station according to an embodiment of the present invention;

fig. 11 is a schematic diagram of a gateway structure provided in an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of an eAN according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of a network system according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The technical scheme provided by the embodiment of the invention is applied to the scene that the terminal is switched between the LTE network and the eHRPD network, and the network architecture is shown in figure 1. In the figure, an LTE network is provided above a dotted line, and provides service to a terminal UE through an eNodeB (evolved base Station), and an eHRPD network is provided below the dotted line, and provides service to the terminal UE through an HRPD BTS (base transceiver Station).

The terminal in the embodiment of the present invention includes a dual-mode terminal and a multi-mode terminal, for example, a dual-mode terminal supporting an LTE network access technology and an eHRPD network access technology, and a multi-mode terminal supporting an HRPD access technology, a CDMA20001x access technology, and an LTE access technology. The dual-mode terminal comprises a single-transmitting dual-receiving terminal and a dual-transmitting dual-receiving terminal. A single-transmitting-dual-receiving terminal refers to a dual-mode terminal having two receivers and one transmitter, which can simultaneously receive information of two networks (different radio access technologies), but can transmit information only in one network at a time, but cannot transmit information in both networks at the same time. The dual transmission and dual reception terminal refers to a dual mode terminal having two receivers and two transmitters, which can simultaneously receive information of two networks and can simultaneously transmit information in the two networks. The cost of the single-transmitting and double-receiving terminal is lower than that of the double-transmitting and double-receiving terminal, one transmitter consumes less power, the cost of the double-transmitting and double-receiving terminal is higher than that of the single-transmitting and double-receiving terminal, and the two transmitters consume more power.

Referring to fig. 2, an embodiment of the present invention provides a network switching method, which may include:

201: a terminal residing in the LTE network registers the eHRPD network through an eHRPD air interface according to the indication of the LTE network;

wherein, the registration process comprises: eHRPD session negotiation, PPP negotiation and EAP-AKA authentication; EAP-AKA is a two-way authentication protocol, and can realize mutual authentication of a terminal and a network;

202: when the terminal decides to switch to the eHRPD network, establishing an air interface connection with the eHRPD network, and triggering the eHRPD network to establish a proxy mobile IP tunnel;

among them, Mobile IP (MIP) is a protocol for realizing IP mobility, and when a user moves between different IP networks, the same IP address can be guaranteed to be allocated. Proxy mobile IP (PMIP, ProxyMobile IP) refers to a network element in a network (such as Serving Gateway in LTE network or HSGW in eHRPD network) acting a terminal to initiate a mobile IP protocol, which does not need the terminal to support the mobile IP protocol, and simplifies the processing of the terminal;

in the embodiment of the invention, the proxy mobile IP tunnel is established between the HSGW and the P-GW;

203: and completing the switching of the terminal from the LTE network to the eHRPD network by the proxy mobile IP tunnel.

The method of the embodiment of the invention can adjust the sequence of each step according to actual needs. The embodiment of the invention registers the eHRPD network through the eHRPD air interface in the LTE network before the terminal determines to initiate the switching from the LTE to the eHRPD, thereby greatly reducing the switching interruption time, improving the user experience, reducing the complexity of the network without increasing an interface between the LTE network and the eHRPD network, and reducing the complexity of the terminal without modifying a protocol stack of the terminal.

An embodiment of the present invention further provides a method for handover from an LTE network to an eHRPD network, where the method includes two procedures of registration and handover, and referring to fig. 3, the registration procedure may include:

301: the terminal is started, and the LTE network is searched by the terminal firstly because the priority of the LTE network is higher than that of the eHRPD network.

302: after the terminal successfully searches the LTE network, the terminal performs a registration process of the LTE network in the LTE network, that is, an Initial Attach process (Initial Attach) of the LTE network, and a proxy mobile IP tunnel established in the registration process is located between the S-GW and the P-GW.

303: after receiving a system broadcast message of an LTE network, a terminal determines whether a preregistration allowed field in the system broadcast message is set to "allowed", that is, determines whether a network side indicates that the terminal is allowed to register to an eHRPD network, if the preregistration field is set to "allowed", the terminal searches for the eHRPD network, and if the preregistration field is set to "not allowed", the terminal does not search for the eHRPD network.

Specifically, if the terminal is a single-transmission double-reception terminal, the terminal searches for an eHRPD network in an LTE idle state; and if the terminal is a dual-transmitting and dual-receiving terminal, searching the eHRPD network by the terminal in an LTE idle state or an LTE activated state.

In this embodiment, the terminal may perform the determination in other manners besides the manner of performing the determination by using the pre-registration field in the system broadcast message, for example, adding a new field in the system broadcast message, and setting the new field to "allow" or "disallow" to indicate that the terminal is currently allowed to register in the eHRPD network, or indicate that the terminal is not currently allowed to register in the eHRPD network.

304: after searching the eHRPD network, the terminal starts to register the eHRPD network through an eHRPD air interface, that is, the initial attachment process of the eHRPD network is started, and the registration process includes: eHRPD air interface session negotiation, PPP negotiation and EAP-AKA authentication, but does not include PDN connection establishment and subsequent procedures. If the terminal is a single-transmitting and double-receiving terminal, the terminal searches an eHRPD network, then switches to an eHRPD mode and starts to register the eHRPD network through an eHRPD air interface, and if the terminal is a double-transmitting and double-receiving terminal, the terminal directly starts to register the eHRPD network through the eHRPD air interface.

305: the terminal sends a VSNCP (bearer Specific Network Control Protocol) configuration request message VSNCP configuration-Req to the HSGW to request establishment of a PDN connection, and an Attach Type (Attach Type) field in the configuration request message is set to "Registration" for example, the value of the field is set to 255 and represents "Registration", and the setting of the Attach Type field to "Registration" is used to indicate that the HSGW in the eHRPD Network does not establish a proxy mobile IP tunnel to the P-GW in the Registration process of the eHRPD Network.

VSNCP is an extended PPP network control protocol that is typically employed in eHRPD networks to establish PDN connections. In this embodiment, the attach type field in the VSNCP configuration request message may be set to: "initial attach", "handover", or "registration". When the attachment type field is set to "initial attachment" or "handover", the HSGW performs a corresponding process flow.

In this step, the PDN ID in the configuration request message may be set to a default PDN ID, which is usually 15. If the terminal establishes a plurality of PDN connections in LTE, the terminal does not initiate the registration of the non-default PDN connection, but establishes the non-default PDN connection after actually switching to the eHRPD network.

306: the HSGW establishes a gateway control session to a PCRF (Policy and Charging Rules Function) entity, which may also be established not when the terminal registers to the eHRPD network, but when the terminal is handed over to the eHRPD network.

307: the HSGW judges whether an attachment type field in the received VSNCP configuration request message is 'registered', if so, a proxy mobile IP tunnel to the P-GW is not established, and VSNCP configuration confirmation message VSNCP Config-Ack is directly returned to the terminal; otherwise, executing corresponding processing flow according to the content of the attachment type field, such as initial attachment flow, switching flow and the like.

308: the HSGW sends a VSNCP configuration request message VSNCP Config-Req to the terminal, and the PDN ID carried in the message is the same as the PDN ID in the VSNCP configuration request message sent by the terminal.

309: after receiving the VSNCP configuration request message sent by the HSGW, the terminal returns a VSNCP configuration acknowledgement message VSNCP Config-Ack to the HSGW, where the VSNCP configuration acknowledgement message carries the PDN ID, so that the terminal completes the registration process to the eHRPD network.

310: and if the terminal meets the condition of residing in the LTE at the moment, releasing the eHRPD air interface connection established in the eHRPD network registration process by the terminal, and entering a dormant state. Generally, a terminal negotiates an air interface session first, then establishes an air interface connection, and after the terminal completes registration to an eHRPD network, may release an eHRPD air interface connection, but the eHRPD air interface session needs to be kept alive, which may keep information of the eHRPD air interface session from being lost through the eHRPD air interface session, where the eHRPD air interface session information includes but is not limited to: the type of protocol negotiated, the attribute values, parameters, etc. used by the negotiation protocol.

311: and when the terminal is a single-transmission double-receiving terminal, the terminal is switched to an LTE mode, and if the terminal is a double-transmission double-receiving terminal, the step is not required to be executed.

Further, if the terminal receives a page from the LTE network in the eHRPD network registration process, the terminal suspends the ongoing eHRPD network registration, fails the registration this time, processes the page from the LTE network, and re-performs the eHRPD network registration when the terminal enters the LTE idle state.

The above process is a registration process of an eHRPD network performed by a terminal residing in an LTE network, and after the terminal completes registration with the eHRPD network, if the terminal satisfies a condition of being handed over to the eHRPD network at a certain time, the terminal may initiate a handover to the eHRPD network, referring to fig. 4, where a handover procedure may include:

401: when the terminal judges that the channel quality of the LTE cell is less than a preset first threshold and the channel quality of the eHRPD cell is higher than a preset second threshold, the terminal judges to switch to the eHRPD network, sends a connection request message ConnectionRequest to a network side in the eHRPD network, and executes a standard connection establishment process. The values of the first threshold and the second threshold are preset respectively, and usually the values of the first threshold and the second threshold are different.

402: after receiving a connection request message sent by a Terminal, an eAN determines, according to a Unicast Access Terminal Identifier (UATI) of the Terminal carried in the message, whether a subnet Identifier (i.e., a Color Code) in the UATI is a self Identifier, if so, it is determined that the UATI update is not required, otherwise, it is determined that the Terminal does not update the UATI in time, the subnet Identifier in the UATI is an Identifier of a source subnet where the Terminal is located, a subnet where the current Terminal is located is a target subnet of the Terminal, and therefore the UATI update is required, and determines, according to the Identifier in the UATI, a source eAN of the Terminal, i.e., an S-eAN in the drawing, and obtains air interface session information of the Terminal from the S-eAN, specifically, an standard a13 session migration process is performed to obtain eHRPD session information from the S-eAN. Fig. 4 illustrates an example of whether the determination result is negative.

403: if the eAN determines that UATI updating is not needed, the eAN sends TCA (traffic channel Assignment message) to the terminal to establish a traffic channel for the terminal; if the eAN determines that UATI updating is needed, sending UATI Assignment information (UATI Assignment) and TCA to the terminal, updating UATI of the terminal and establishing a traffic channel for the terminal.

The UATI comprises a subnet identification and a terminal identification, wherein the subnet identification is used for identifying different subnets, and each subnet identification uniquely corresponds to one subnet and eAN of the subnet; the terminal identification is uniquely valid within the subnet for identifying the terminal within the subnet.

404: if the terminal receives TCA, then returning TCC (Traffic Channel Complete message) to eAN to indicate that the establishment of the Traffic Channel is successful; if the terminal receives the UATI Assignment message and the TCA, the terminal returns a UATI Assignment Complete message (UATI Assignment Complete) and TCC, which indicates that the UATI update is Complete and the traffic channel is successfully established.

405: the eAN sends an A11 Registration Request message (A11-Registration Request) to the HSGW, wherein the message contains an activation-Start (Active-Start) charging record, which indicates that the terminal has accessed the eHRPD network.

406: after receiving the a11 registration request message, the HSGW determines whether the message contains an Active-Start charging record, if so, it indicates that a service channel has been established for the terminal, and the HSGW sends a proxy mobile IP Binding Update message (PMIP Binding Update) to the P-GW to establish a proxy mobile IP tunnel.

407: the P-GW and the PCRF interact, report an event of RAT (Radio Access Type) change, initiate an IP-CAN session modification process, and update the IP-CAN session.

408: the P-GW returns a proxy mobile IP Binding acknowledgement message (PMIP Binding Ack), which may also be performed after 406.

409: the HSGW returns an a11 Registration Reply message (a 11-Registration Reply) message to the eAN, the proxy mobile IP tunnel establishment is completed, the handover of the terminal to the eHRPD network is completed, and this step may also be executed after 405.

410: if there is a special QoS (Quality of Service) flow before the terminal is switched to the eHRPD network, the HSGW uses an RSVP (Resource reSerVation Protocol) Protocol to inform the terminal to establish a corresponding QoS flow. This step is an optional step, represented by the dashed line in the figure.

411: and if the terminal establishes a plurality of PDN connections before being switched to the eHRPD network, the terminal initiates non-default PDN connection establishment after the switching. This step is also an optional step, indicated by the dashed line in the figure.

In addition, 410 and 411 can also be performed in parallel, a dedicated QoS flow belonging to a certain PDN is established after a corresponding PDN connection is established, and if the dedicated QoS flow is failed to be established, the PCRF is notified to delete the corresponding QoS flow.

412: and the P-GW sends a Binding release Indication message (Binding release Indication) to the S-GW and triggers the release of the resources of the LTE side.

Fig. 3 and 4, taken together, describe the flow of registration and handover in its entirety. Further, after the terminal completes registration of the eHRPD network, it may also maintain the eHRPD air interface session, including air interface session keep-alive and subnet change processing, referring to fig. 5, the air interface session keep-alive process may specifically include:

501: the terminal resides in the LTE network after completing registration of the eHRPD network.

502: the eAN sends a keep-alive request message (KeepAliveRequest) to the terminal to perform eHRPD air interface session detection.

503: after receiving the keep-alive request message, the terminal determines whether the currently received system broadcast message on the LTE network side indicates permission to register to the eHRPD network, if it determines whether a pre-registration field (preregistration allowed) is "permission", if so, performs eHRPD air interface session keep-alive processing, otherwise, does not perform eHRPD session keep-alive processing, and in this case, if the eAN detects that a preset keep-alive timeout time is up, deletes the eHRPD air interface session, and exits the registration state.

The terminal performs eHRPD air interface session keep-alive processing, which may specifically include:

if the terminal is a dual-transmission dual-reception terminal, the dual-transmission dual-reception terminal performs air interface session keep-alive processing in the eHRPD network;

if the terminal is a single-transmitting double-receiving terminal, the single-transmitting double-receiving terminal judges the state of the terminal, if the terminal is in an LTE idle state, the terminal is switched to an eHRPD mode to carry out air interface session keep-alive processing, if the terminal is in an LTE activated state, whether preset keep-alive overtime time is reached is judged, if the preset keep-alive overtime time is reached, the terminal is switched to the eHRPD mode to carry out air interface session keep-alive processing, otherwise, an identifier is set to indicate that the air interface session keep-alive processing is carried out when the single-transmitting double-receiving terminal enters the.

The preset keep-alive timeout time can be set to different values according to needs, for example, the preset 18 hours is the keep-alive timeout time. Further, the number of times of keep-alive timeout can be preset, for example, when the keep-alive timeout reaches 3 times, the air interface session is deleted, and when the single-transmission and double-reception terminal is in an LTE activated state, if the keep-alive timeout reaches 3 rd time, the terminal is immediately switched to an eHRPD mode to perform the keep-alive processing of the air interface session.

504: the terminal returns a keep-alive response message (KeepAliveResponse) to the eAN, and the eAN continues to keep the existing air interface session information.

505: and the terminal closes the eHRPD transmitter and switches to the LTE mode, namely tunes to the LTE network.

The terminal can maintain the air interface session through the air interface session keep-alive processing, and ensure that the air interface session information is not lost, thereby avoiding renegotiating the air interface session during the switching execution and reducing the time for switching the terminal.

Referring to fig. 6, after the terminal completes registration of the eHRPD network, subnet change processing may also be performed, including:

601: the terminal resides in the LTE network after completing registration of the eHRPD network.

602: the eAN periodically broadcasts fast configuration and sector parameters messages (QuickConfig & SectorParameters).

603: after receiving the rapid configuration and sector parameter message, the terminal judges whether a subnet in the eHRPD network changes according to the content of the rapid configuration and sector parameter message, if the subnet changes, namely the terminal has moved from a source subnet to a target subnet, whether the currently received system broadcast message on the LTE network side indicates that the registration to the eHRPD network is allowed is judged, if so, UATI updating is carried out when the terminal is in an LTE idle state, or UATI updating is not carried out when the terminal is in an LTE activated state, UATI updating is carried out after the terminal enters the LTE idle state, and if the terminal keeps the LTE activated state until the terminal is switched to the eHRPD network, UATI updating is carried out while the terminal is switched.

If the terminal is a single-transmitting double-receiving terminal, the UATI is updated after the terminal is switched to an eHRPD mode, and if the terminal is a double-transmitting double-receiving terminal, the UATI is directly updated in an eHRPD network.

604: the terminal executes UATI assignment process, acquires new UATI from T-eAN/PCF of the target subnet, if the source subnet and the target subnet belong to the same eAN, the eAN re-allocates a UATI to the terminal; if the source subnet and the target subnet belong to different eANs, the T-eAN/PCF of the target subnet executes A13 session to migrate eHRPD air interface session information from the S-eAN/PCF of the source subnet, allocates new UATI and then sends the UATI to the terminal.

605: and when the terminal is a single-transmitting and double-receiving terminal, closing the eHRPD transmitter, tuning to the LTE network, and if the terminal is a double-transmitting and double-receiving terminal, not executing the step.

The terminal can ensure that UATI is updated through subnet changing processing, and the eHRPD air interface session information is migrated from the source S-eAN/PCF, thereby avoiding the loss of the negotiated air interface session information, avoiding renegotiating the air interface session during the switching execution and reducing the switching interruption time.

In addition, in the embodiment of the present invention, after the terminal performs registration of the eHRPD network, PPP session maintenance may also be performed, which is specifically as follows:

when the terminal receives the PPP session detection message sent by the HSGW, if the terminal is in the LTE network, the PPP session detection message is not responded.

When the eAN air interface session keep-alive detection is overtime, the eHRPD air interface session is released, correspondingly, the eAN/PCF initiates the connection release of the main A10, and the HSGW is triggered to release the PPP session.

Typically, the HSGW treats all users as Always-on users (i.e., Always-on), and the HSGW does not implement PPP Session timer Session timing. The default value of the PPP inactivity period (PPP inactivity timer) in the HSGW is 0, that is, the PPP inactivity period is infinite, and the HSGW does not initiate PPP session detection. Preferably, the PPP inactivity period uses a default value of 0, when the PPP inactivity period is configured to be a non-zero value, the HSGW sends an LCP Echo Request message to the terminal for PPP session detection when the inactivity period reaches a specified time, and after receiving the PPP session detection message, the terminal does not return an LCP Echo Reply response message if the terminal currently resides in the LTE network, so that the HSGW releases the PPP session and reestablishes PPP when the terminal is next handed over to the eHRPD network.

The terminal carries out PPP session maintenance, does not respond to PPP session detection of the HSGW, and can prevent a service channel from being established for the terminal due to the response of the PPP session, so that the network side can identify that the terminal is switched to the eHRPD network, and unnecessary switching from the LTE network to the eHRPD network can be caused.

In this embodiment of the present invention, further, after the terminal completes registration with the eHRPD network, before the eHRPD air interface connection is not released, if the terminal meets a condition for switching to the eHRPD network right now, the terminal may perform a handover procedure by using the unreleased eHRPD air interface connection, referring to fig. 7, which may specifically include:

701: the terminal completes the registration from the LTE network to the eHRPD network, before the eHRPD air interface connection is not released, the terminal detects that the terminal meets the condition of switching to the eHRPD network, a VSNCP configuration request message VSNCPConfig-Req is sent to the HSGW, an attachment type field in the message is set to be switched and attached (HandoverAttach), and the establishment of a proxy mobile IP tunnel is triggered.

702: after the HSGW receives the VSNCP configuration request message, because eHRPD air interface connection already exists, it is not necessary to re-establish eHRPD air interface connection, and UATI update and establish a traffic channel, directly establish a proxy mobile IP tunnel, and complete the handover of the terminal to the eHRPD network using the proxy mobile I P tunnel. The HSGW establishes a proxy mobile IP tunnel and the terminal completes the handover process to the eHRPD network, which is specifically the same as 406 to 412 in the embodiment of the present invention, and details are not described here.

The method of the embodiment of the invention can adjust the sequence of each step according to actual needs.

The method provided by the embodiment of the invention registers through the eHRPD air interface before the terminal is switched to the eHRPD network, completes eHRPD air interface session negotiation, PPP negotiation and EAP-AKA authentication before the switching from LTE to eHRPD occurs, only establishes eHRPD air interface connection and switches the proxy mobile IP tunnel during the switching, and greatly reduces the service interruption time of the switching from the LTE network to the eHRPD network. Compared with the existing optimized handover, the handover is not completed through LTE and S101 tunnels, and the complexity of the network is greatly reduced. And moreover, the protocol stack of the terminal does not need to be modified, and the complexity of the terminal is reduced. In addition, after the terminal completes the eHRPD network registration, when the terminal is in an LTE idle state, the terminal performs the air interface session keep-alive and subnet change processing as needed, so as to ensure that the terminal does not exit the eHRPD registration state, thereby ensuring the validity of the eHRPD registration. By preferentially executing eHRPD air interface session information maintenance in an LTE idle state, the influence on the ongoing service of an LTE network can be avoided, the service quality is improved, and the user experience is improved.

Referring to fig. 8, an embodiment of the present invention further provides a network switching method, which may specifically include:

801: the LTE network side sends a message to the terminal to indicate that the terminal is allowed to register the eHRPD network;

802: when the terminal finishes the registration to the eHRPD network through the eHRPD air interface and decides to switch to the eHRPD network, the eHRPD network side establishes a proxy mobile IP tunnel, and the proxy mobile IP tunnel finishes the switching from the terminal to the eHRPD network.

Further, the method may further include:

in the registration process of an eHRPD network of a terminal, an HSGW at the eHRPD network side receives a configuration request message of a device provider extension network control protocol VSNCP sent by the terminal; the HSGW judges whether the attachment type field carried in the configuration request message is registered, if so, the HSGW does not establish a proxy mobile IP tunnel to the packet data network gateway in the registration process.

Further, the method may further include:

after the terminal finishes the registration to the eHRPD network, an eAN at the eHRPD network side sends an air interface session keep-alive request message to the terminal; and the eAN receives an air interface session keep-alive response message returned by the terminal according to the indication of the LTE network side and the state of the terminal.

Further, the method may further include:

when the terminal finishes the registration to the eHRPD network and detects that the subnet in the eHRPD network changes, the eAN of the target subnet where the terminal is currently located judges whether the eAN is the eAN of the source subnet where the terminal is located before the subnet changes, if so, the eAN allocates an access terminal unicast identifier UATI to the terminal, otherwise, the eAN of the target subnet migrates eHRPD air interface session information from the eAN of the source subnet, allocates a new UATI to the terminal, and then sends the UATI to the terminal.

Further, before establishing the proxy mobile IP tunnel on the eHRPD network side, the method may further include:

an eAN at an eHRPD network side receives a connection request message sent by a terminal in the eHRPD network;

the eAN judges whether a subnet identification in a unicast identification of an access terminal of the terminal is an identification of the eAN according to the connection request message;

if yes, eAN sends a service channel assignment message to the terminal to establish a service channel for the terminal;

otherwise, the eAN determines the source eAN of the terminal according to the subnet identification in the unicast identification of the access terminal, acquires the empty port session information of the terminal from the source eAN, then sends the unicast identification assignment message of the access terminal and the assignment message of the service channel to the terminal, updates the unicast identification of the access terminal of the terminal, and establishes the service channel for the terminal.

Referring to fig. 9, an embodiment of the present invention further provides a terminal, which may include:

a registration module 901, configured to perform registration of an eHRPD network through an eHRPD air interface according to an instruction of the LTE network when the terminal is camped on the LTE network;

a triggering module 902, configured to establish an air interface connection after the registration module 901 completes registration and the terminal determines to switch to the eHRPD network, and trigger the eHRPD network to establish a proxy mobile IP tunnel from the HSGW to the P-GW, where the proxy mobile IP tunnel is used to complete switching of the terminal from the LTE network to the eHRPD network.

When the terminal is a single-transmitting and dual-receiving terminal, the registration module 901 may specifically include:

a first registration unit, configured to, if a single-transmitting and double-receiving terminal residing in an LTE network receives a system broadcast message of an LTE network side and the system broadcast message indicates permission to register to an eHRPD network, switch to an eHRPD mode to register the eHRPD network through an eHRPD air interface when the single-transmitting and double-receiving terminal is in an LTE idle state;

when the terminal is a dual-transmission and dual-reception terminal, the registration module 901 may specifically include:

a second registration unit, configured to perform registration of the eHRPD network over an eHRPD air interface when the dual-transmitting and dual-receiving terminal in the LTE network receives the system broadcast message of the LTE network side and indicates permission to register to the eHRPD network in the system broadcast message, if the dual-transmitting and dual-receiving terminal is in an LTE idle state or an LTE activated state.

Further, the terminal may further include:

a connection establishing module, configured to send a device provider extension network control protocol VSNCP configuration request message to an eHRPD network side in a registration process of the eHRPD network by the terminal, to request establishment of a packet data network connection, and when the content of the attach type field carried in the configuration request message is registration, indicate that an HSGW in the eHRPD network does not establish a proxy mobile IP tunnel from the HSGW to the P-GW in the registration process.

Further, when the terminal is a dual-transmitting and dual-receiving terminal, the method may further include:

the first air interface session keep-alive module is used for carrying out air interface session keep-alive processing on the dual-transmitting and dual-receiving terminal if the indication in the system broadcast message of the LTE network side currently received by the dual-transmitting and dual-receiving terminal is that the dual-transmitting and dual-receiving terminal is allowed to be registered to the eHRPD network when the dual-transmitting and dual-receiving terminal receives an air interface session keep-alive request message sent by an evolved access network eAN after the dual-transmitting and dual-receiving terminal carries out registration of the eHRPD network;

or, when the terminal is a single-transmitting and double-receiving terminal, the method may further include:

and the second air interface session keep-alive module is used for judging the state of the single-transmitting and double-receiving terminal when the single-transmitting and double-receiving terminal receives an air interface session keep-alive request message sent by eAN after the single-transmitting and double-receiving terminal registers the eHRPD network, if the indication in the system broadcast message of the LTE network side currently received by the single-transmitting and double-receiving terminal is that the registration to the eHRPD network is allowed, if the indication is in an LTE idle state, carrying out air interface session keep-alive processing, if the indication is in an LTE activated state, judging whether the preset keep-alive overtime time is reached, if the indication is in an LTE activated state, carrying out air interface session keep-alive processing, and if the indication is not, indicating that the air interface session keep-alive processing is carried out when the single-transmitting and double.

Further, the terminal may further include:

and the subnet change processing module is used for updating the unicast identifier of the access terminal when the terminal receives a system broadcast message of the LTE network side currently and indicates that the terminal is allowed to register to the eHRPD network after the terminal registers the eHRPD network, or updating the unicast identifier of the access terminal in the process of switching to the eHRPD network when the terminal is in an LTE idle state.

Further, the terminal may further include:

and the point-to-point session maintenance module is used for not responding to the point-to-point session detection message if the terminal is in the LTE network when the terminal receives the point-to-point session detection message sent by the high-rate packet data service gateway after the terminal registers in the eHRPD network.

The modules of the embodiment of the invention can be integrated into a whole or can be separately deployed. The modules can be combined into one module, and can also be further split into a plurality of sub-modules.

The terminal provided by the embodiment of the invention registers through the eHRPD air interface before being switched to the eHRPD network, completes eHRPD air interface session negotiation, PPP negotiation and EAP-AKA authentication before the switching from LTE to eHRPD occurs, only establishes eHRPD air interface connection and switches the proxy mobile IP tunnel during the switching, and greatly reduces the service interruption time of the switching from the LTE network to the eHRPD network. Compared with the existing optimized handover, the handover is not completed through LTE and S101 tunnels, and the complexity of the network is greatly reduced. And moreover, the protocol stack of the terminal does not need to be modified, and the complexity of the terminal is reduced. In addition, after the terminal completes the eHRPD network registration, when the terminal is in an LTE idle state, the terminal performs the air interface session keep-alive and subnet change processing as needed, so as to ensure that the terminal does not exit the eHRPD registration state, thereby ensuring the validity of the eHRPD registration. By preferentially executing eHRPD air interface session information maintenance in an LTE idle state, the influence on the ongoing service of an LTE network can be avoided, the service quality is improved, and the user experience is improved.

Referring to fig. 10, an embodiment of the present invention further provides a base station, located in an LTE network, and including:

a message generating module 1001, configured to generate a message indicating that registration of the eHRPD network by the terminal is allowed;

a sending module 1002, configured to send the message generated by the message generating module 1001 to a terminal residing in an LTE network, and indicate that the terminal is allowed to register in the eHRPD network, so that the terminal performs registration in the eHRPD network over an eHRPD air interface.

The base station provided by the embodiment of the invention allows the terminal to register the eHRPD network by indicating the terminal, so that the terminal can complete the registration to the eHRPD network before the switching from the LTE network to the eHRPD network occurs, and the service interruption time of the switching from the LTE network to the eHRPD network is greatly reduced.

An embodiment of the present invention further provides a gateway, located in an eHRPD network, and may include:

and the tunnel establishment module is used for establishing a proxy mobile IP tunnel and completing the switching of the terminal to the eHRPD network through the proxy mobile IP tunnel when the terminal completes the registration from the LTE network to the eHRPD network and decides to switch to the eHRPD network.

Further, referring to fig. 11, the gateway may further include:

a receiving module 1101, configured to receive a device vendor extension network control protocol VSNCP configuration request message sent by a terminal in a registration process of an eHRPD network;

correspondingly, the tunnel establishing module 1102 may be specifically configured to determine whether the content of the attach type field carried in the VSNCP configuration request message received by the receiving module 1101 is registration, if so, not establish a proxy mobile IP tunnel to the packet data network gateway P-GW in the registration process, and when the terminal completes registration from the LTE network to the eHRPD network and determines to handover to the eHRPD network, establish a proxy mobile IP tunnel to the P-GW, and complete handover of the terminal to the eHRPD network through the proxy mobile IP tunnel, otherwise, perform corresponding processing according to the content of the attach type field.

The gateway provided by the embodiment of the invention does not establish the proxy mobile IP tunnel when the field is the registration by judging the attachment type field, and can realize that the proxy mobile IP tunnel is not established when the terminal performs eHRPD network registration, thereby greatly shortening the service interruption time of the switching when the terminal is switched to the eHRPD network.

Referring to fig. 12, an eAN in an eHRPD network according to an embodiment of the present invention may include at least one of the following three modules:

an air interface session keep-alive module 1201, configured to send an air interface session keep-alive request message to the terminal after the terminal completes registration from the LTE network to the eHRPD network, and receive an air interface session keep-alive response message returned by the terminal according to the indication of the LTE network side and the state of the terminal;

a subnet change processing module 1202, configured to, when the terminal completes registration from the LTE network to the eHRPD network and detects that a subnet in the eHRPD network changes, determine, as an eAN of a target subnet where the terminal is currently located, whether the eAN itself is an eAN of a source subnet where the terminal is located before the subnet changes, if yes, allocate an access terminal unicast identifier UATI to the terminal, otherwise, migrate eHRPD air interface session information from the eAN of the source subnet, allocate an UATI to the terminal, and then send the UATI to the terminal;

a traffic channel establishing module 1203, configured to receive a connection request message sent by the terminal in the eHRPD network after the terminal is determined to be switched to the eHRPD network, determine whether a subnet id in an access terminal unicast identifier UATI of the terminal is an identifier of the eAN according to the connection request message, if so, send a traffic channel assignment message to the terminal, and establish a traffic channel for the terminal, otherwise, determine a source eAN of the terminal according to the subnet id in the UATI, and obtain air interface session information of the terminal from the source eAN, then send an access terminal unicast identifier assignment message and a traffic channel assignment message to the terminal, update the UATI of the terminal, and establish a traffic channel for the terminal.

Fig. 12 illustrates an example where the eAN includes the three modules, and in practical applications, the eAN may include only one or two of the three modules.

The eAN provided by the embodiment of the invention can ensure that the terminal cannot exit the eHRPD registration state by performing the air interface session keep-alive processing and subnet change processing, thereby ensuring the validity of the eHRPD registration; the air interface session migration of the terminal is carried out according to the UATI of the terminal, so that when the terminal is switched to the eHRPD network from the LTE network, the eHRPD air interface session negotiation does not need to be carried out again, and the subnet change processing is not required to be carried out immediately when the terminal detects the subnet change of the eHRPD network in the LTE activated state.

Referring to fig. 13, an embodiment of the present invention further provides a network system, which may include:

the terminal 1301 is used for registering the eHRPD network through an eHRPD air interface according to the indication of the LTE network when the terminal is resident in the LTE network, then establishing air interface connection, and triggering the eHRPD network to establish a proxy mobile IP tunnel from the HSGW to the P-GW, wherein the proxy mobile IP tunnel is used for completing the switching of the terminal from the LET network to the eHRPD network;

a base station 1302 located in the LTE network, configured to send a message to the terminal when the terminal resides in the LTE network, where the message indicates that the terminal is allowed to register in the eHRPD network, and specifically, the base station may be an eNodeB;

and the high-rate packet data service gateway HSGW 1303 is located in the eHRPD network and used for establishing a proxy mobile IP tunnel from the terminal to the P-GW and completing the handover of the terminal to the eHRPD network through the proxy mobile IP tunnel when the terminal completes the registration from the LTE network to the eHRPD network and decides to handover to the eHRPD network.

Further, the system may further include: the eAN is positioned in the eHRPD network and at least comprises one of the following three modules:

the air interface session keep-alive module is used for sending an air interface session keep-alive request message to the terminal after the terminal finishes the registration from the LTE network to the eHRPD network and receiving an air interface session keep-alive response message returned by the terminal according to the indication of the LTE network side and the state of the terminal;

a subnet change processing module, configured to, when the terminal completes registration from the LTE network to the eHRPD network and detects that a subnet in the eHRPD network changes, determine, as an eAN of a target subnet where the terminal is currently located, whether the eAN itself is the eAN of a source subnet where the terminal is located before the subnet changes, if yes, allocate an access terminal unicast identifier UATI to the terminal, otherwise, migrate an eHRPD session information from the eAN of the source subnet, allocate an UATI to the terminal, and then send the information to the terminal;

a service channel establishing module, configured to receive a connection request message sent in an eHRPD network after the terminal is determined to be switched to the eHRPD network, determine whether a subnet identifier in an access terminal unicast identifier UATI of the terminal is an identifier of the eAN according to the connection request message, if so, send a service channel assignment message to the terminal, establish a service channel for the terminal, otherwise, determine a source eAN of the terminal according to the subnet identifier in the UATI, acquire air interface session information of the terminal from the source eAN, then send an access terminal unicast identifier assignment message and a service channel assignment message to the terminal, update the UATI of the terminal, and establish a service channel for the terminal.

Each unit of the system according to the embodiment of the present invention may be integrated into one device, or may be distributed in a plurality of devices. The units may be combined into one unit, or further divided into a plurality of sub-units.

The system provided by the embodiment of the invention performs registration of the eHRPD network before the terminal is switched to the eHRPD network, completes eHRPD air interface session negotiation, PPP negotiation and EAP-AKA authentication before the LTE network is switched to the eHRPD network, only establishes eHRPD air interface connection and performs switching of the proxy mobile IP tunnel during switching, and greatly reduces service interruption time for switching the LTE network to the eHRPD network. Compared with the existing optimized handover, the handover is not completed through LTE and S101 tunnels, and the complexity of the network is greatly reduced. And moreover, the protocol stack of the terminal does not need to be modified, and the complexity of the terminal is reduced. In addition, after the terminal completes the eHRPD network registration, when the terminal is in an LTE idle state, the terminal performs the air interface session keep-alive and subnet change processing as needed, so as to ensure that the terminal does not exit the eHRPD registration state, thereby ensuring the validity of the eHRPD registration. By preferentially executing eHRPD air interface session information maintenance in an LTE idle state, the influence on the ongoing service of an LTE network can be avoided, the service quality is improved, and the user experience is improved.

Through the above description of the embodiments, those skilled in the art will clearly understand that the present invention may be implemented by software plus a necessary general hardware platform, and may also be implemented by hardware, or a combination of the two. Based on such understanding, the technical solutions of the present invention may be embodied in the form of software products, which are stored in a storage medium and include instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute the methods according to the embodiments of the present invention. The storage medium may be Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A network switching method is applied to a Long Term Evolution (LTE) network and an evolved high rate packet data (eHRPD) network, and comprises the following steps:

2. The network handover method according to claim 1, wherein the method further comprises:

in the registration process of the eHRPD network of the terminal, a high-rate packet data service gateway (HSGW) at the eHRPD network side receives a request message sent by the terminal;

the HSGW judges whether an attachment type field carried in the request message is registered, if so, the HSGW does not establish a proxy mobile IP tunnel to a packet data network gateway in the registration process.

3. The network handover method according to claim 1, wherein the method further comprises:

after the terminal finishes registering to an eHRPD network, an evolved access network eAN at the eHRPD network side sends an air interface session keep-alive request message to the terminal;

and the eAN receives an air interface session keep-alive response message returned by the terminal according to the indication of the LTE network side and the state of the eAN.

4. The network handover method according to claim 1, wherein the method further comprises:

when the terminal finishes the registration to an eHRPD network and detects that a subnet in the eHRPD network changes, an eAN of a target subnet where the terminal is located currently allocates an access terminal unicast identifier UATI to the terminal and sends the UATI to the terminal.

5. The network handover method according to claim 1, wherein before the eHRPD network side establishes the proxy mobile IP tunnel, the method further comprises:

the eAN at the side of the eHRPD network receives a connection request message sent by the terminal in the eHRPD network;

if yes, the eAN sends a service channel assignment message to the terminal to establish a service channel for the terminal;

otherwise, the eAN determines the source eAN of the terminal according to the subnet identification in the unicast identification of the access terminal, acquires the air interface session information of the terminal from the source eAN, then sends an access terminal unicast identification assignment message and a service channel assignment message to the terminal, updates the unicast identification of the access terminal of the terminal, and establishes a service channel for the terminal.

6. A terminal, comprising:

7. The terminal of claim 6, wherein the registration module comprises:

a first registration unit, configured to, if the terminal residing in the LTE network receives a message from the LTE network and the message indicates that registration to the eHRPD network is allowed, switch to an eHRPD mode to perform registration of the eHRPD network through an eHRPD idle port when the terminal is in an LTE idle state;

or,

a second registration unit, configured to perform registration of the eHRPD network over an eHRPD air interface when the terminal is in an LTE idle state or an LTE activated state, if the terminal residing in the LTE network receives a message from the LTE network and the message indicates permission to register to the eHRPD network.

8. The terminal of claim 6, further comprising:

a connection establishing module, configured to send a request message to an eHRPD network side to request establishment of packet data network connection in a registration process of the eHRPD network performed by the terminal, and indicate that a high-rate packet data serving gateway HSGW in the eHRPD network is not used to establish a proxy mobile IP tunnel from the HSGW to a packet data network gateway P-GW in the registration process when the content of an attachment type field carried in the request message is registration.

9. The terminal of claim 6, further comprising:

a first air interface session keep-alive module, configured to, after the terminal performs registration in the eHRPD network, when the terminal receives an air interface session keep-alive request message sent by an evolved access network eAN, if an indication in a message on an LTE network side currently received by the terminal indicates that registration in the eHRPD network is allowed, perform air interface session keep-alive processing on the terminal;

or,

a second air interface session keep-alive module, configured to, after the terminal performs registration of the eHRPD network, when the terminal receives an air interface session keep-alive request message sent by the eAN, if an indication in a message on the LTE network side currently received by the terminal indicates that registration to the eHRPD network is allowed, the terminal determines a state of the terminal, if the terminal is in an LTE idle state, performs air interface session keep-alive processing, if the terminal is in an LTE activated state, determines whether a preset keep-alive timeout time is reached, if the terminal is in an LTE activated state, performs air interface session keep-alive processing, otherwise, sets an identifier, and indicates that the terminal performs air interface keep-alive session processing when the terminal enters the LTE idle state.

10. The terminal of claim 6, further comprising:

a subnet change processing module, configured to, after the terminal performs registration in the eHRPD network, when the terminal detects that a subnet in the eHRPD network changes, if an indication in a message received by the terminal at the LTE network side currently indicates that registration to the eHRPD network is allowed, perform unicast identifier update of the access terminal when the terminal is in an LTE idle state, or perform unicast identifier update of the access terminal in a process of switching to the eHRPD network when the terminal is in an LTE active state.

11. The terminal of claim 6, further comprising:

and the point-to-point session maintenance module is used for not responding to the point-to-point session detection message if the terminal is in the LTE network when the terminal receives the point-to-point session detection message from the high-rate packet data service gateway after the terminal registers in the eHRPD network.

12. A gateway in an evolved high rate packet data, eHRPD, network, the gateway comprising:

13. A network system, comprising:

14. The network system of claim 13, wherein the system further comprises: an evolved access network eAN located in the eHRPD network;

the eAN at least comprises one of the following three modules:

an air interface session keep-alive module, configured to send an air interface session keep-alive request message to a terminal after the terminal completes registration from an LTE network to the eHRPD network, and receive an air interface session keep-alive response message returned by the terminal according to an indication of the LTE network side and a state of the terminal;

a subnet change processing module, configured to, when a terminal completes registration from an LTE network to the eHRPD network and detects that a subnet in the eHRPD network changes, allocate an access terminal unicast identifier UATI to the terminal as an eAN of a target subnet where the terminal is currently located, and send the UATI to the terminal;

a service channel establishing module, configured to receive a connection request message sent by a terminal in an eHRPD network after the terminal is determined to be switched to the eHRPD network, determine whether a subnet identifier in an access terminal unicast identifier UATI of the terminal is an identifier of the eAN according to the connection request message, if so, send a service channel assignment message to the terminal, and establish a service channel for the terminal, otherwise, determine a source eAN of the terminal according to the subnet identifier in the UATI, obtain air interface session information of the terminal from the source eAN, send an access terminal unicast identifier assignment message and a service channel assignment message to the terminal, update the UATI of the terminal, and establish a service channel for the terminal.

15. The network system according to claim 13, wherein the base station comprises:

a message generation module, configured to generate a message indicating that registration of an evolved high rate packet data eHRPD network is allowed for a terminal;

a sending module, configured to send the message generated by the message generating module to a terminal residing in the LTE network, and indicate that the terminal is allowed to perform registration of an evolved high rate packet data eHRPD network, so that the terminal performs registration of the eHRPD network over an eHRPD air interface.