CN103476073B - Cell falling-back method and equipment - Google Patents

Abstract

The present invention provides a cell fallback method and equipment. The mobile terminal starts CSFB fallback; the mobile terminal supports the first SIM card of the LTE standard and the second SIM card of the 2G/3G standard; the mobile terminal acquires the second SIM card from the storage unit The network information of the first cell to which the card is currently attached; the mobile terminal sends the network information to the MME, so that the MME sends the network information to the second base station corresponding to the cell to which the first SIM card is attached, and makes the second base station according to the network information Sending a handover request to the first base station; the mobile terminal receives a handover instruction sent by the second base station; the handover instruction is sent by the first base station after receiving the handover request and allowing the CS domain under the first SIM card to fall back to the first cell For the second base station; the mobile terminal falls back the CS domain under the first SIM card to the first cell according to the handover instruction. Using the cell fallback method in the present invention can reduce CS domain call delay.

Description

Community fallback method and equipment

technical field

The present invention relates to communication technology, in particular to a cell fallback method and equipment.

Background technique

In the initial stage of Long Term Evolution (LTE for short) network deployment, the LTE network mainly provides broadband data services, while the voice service solutions of most operators adopt Circuit Switched Fallback (CSFB for short) technology, that is, mobile terminals execute Voice and other CS domain services need to fall back to the second-generation mobile communication technology (2G for short)/3rd-generation mobile communication technology (3rd-generation, 3G for short) network to take advantage of the high Coverage and mature technology provide voice service support for LTE network users.

At present, in the LTE network, after the mobile terminal is powered on, the LTE standard smart card (Subscriber Identity Module, SIM for short) will jointly register the Packet Switched (PS) domain and the CS domain, through the Mobility Management Entity (Mobility Management Entity) Entity (MME for short) attaches the PS domain to the LTE network, and attaches the CS domain to the 2G/3G network. When the SIM card receives or initiates a CS domain service, when the mobile terminal uses CSFB technology to perform cell fallback, the cell it was attached to may not be the best cell where the terminal is located, and the location of the mobile terminal may change with the The mobile terminal changes due to the movement of the mobile terminal. In this case, the cell to which the mobile terminal attaches when it is turned on may not meet the service requirements of the mobile terminal. At this time, the mobile terminal needs to search the network again to obtain a suitable target. The cell is handed over, but with the existing CSFB technology, because the mobile terminal re-searches to obtain the target cell, the call flow of the CS domain service will be increased, resulting in an increase in the call delay of the CS domain service and affecting user experience.

Contents of the invention

The invention provides a cell fallback method and equipment, which are used to solve the problem of long call delay when the cell fallback is realized through the existing CSFB technology.

In order to achieve the above object, the present invention provides a cell fallback method, including:

The mobile terminal starts CSFB fallback, and the mobile terminal supports the first SIM card of the LTE standard and the second SIM card of the 2G/3G standard;

The mobile terminal obtains the network information of the first cell to which the second SIM card is currently attached from the storage unit; the network information is that after the second SIM card is attached to the first cell, the first The first base station corresponding to the cell sends to the mobile terminal;

The mobile terminal sends the network information to a mobility management entity MME, so that the MME sends the network information to a second base station corresponding to the cell to which the first SIM card is attached, and makes the second base station sending a handover request to the first base station according to the network information;

The mobile terminal receives a handover instruction sent by the second base station; the handover instruction is sent by the first base station to the second cell after receiving the handover request and allowing the fallback to the first cell of the second base station;

The mobile terminal falls back the CS domain under the first SIM card to the first cell according to the handover instruction.

In order to achieve the above object, the present invention provides a mobile terminal, including:

Start module, be used for starting CSFB to fall back;

An acquisition module, configured to acquire the network information of the first cell to which the second SIM card is currently attached from the storage unit; the network information is that after the second SIM card is attached to the first cell, the sent by the first base station corresponding to a cell to the mobile terminal;

A sending module, configured to send the network information to the MME, so that the MME sends the network information to a second base station corresponding to the cell to which the first SIM card is attached, and makes the second base station sending a handover request to the first base station according to the network information;

A receiving module, configured to receive a handover instruction sent by the second base station; the handover instruction is sent by the first base station after receiving the handover request and allowing the CS domain under the first SIM card to fall back to the sent to the second base station in the first cell;

A fallback module, configured to fall back the CS domain under the first SIM card to the first cell according to the handover instruction;

Wherein, the mobile terminal supports the first SIM card of the LTE standard and the second SIM card of the 2G/3G standard.

The invention provides a cell fallback method and equipment. The mobile terminal starts CSFB fallback, obtains from the storage unit the network information of the first cell to which the second SIM card is currently attached, and sends it to the MME, so that the MME sends the network information of the first cell to the cell to which the first SIM card is currently attached. The second base station corresponding to the cell, and the second base station sends a handover request to the first base station corresponding to the first cell according to the network information, and the mobile terminal receives the handover instruction sent by the second base station; the handover instruction is received by the first base station after receiving the handover request It is sent to the second base station after the request and when the CS domain under the first SIM card is allowed to fall back to the first cell, and the mobile terminal falls back the CS domain under the first SIM card to the first cell according to the handover instruction. In the present invention, the mobile terminal includes a first SIM card of LTE standard and a second SIM card of 2G/3G standard, and stores the network information of the cell currently attached to the second SIM card locally in the mobile terminal. When the first SIM card of the mobile terminal needs to perform CSFB fallback, if the cell attached to the first SIM card in the 2G/3G network cannot meet the service requirements due to the location change of the mobile terminal, the mobile terminal can directly connect to the cell from the 2G/3G network. The network information of the cell currently attached to the second SIM card is obtained locally, and when the base station corresponding to the cell attached to the second SIM card allows the mobile terminal to fall back, the mobile terminal is directly dropped back to the cell currently attached to the second SIM card, so that The CS domain service of the first SIM card can be connected, so that the mobile terminal does not need to search for the target cell again for the CS domain under the first SIM card, which overcomes the problem of long call delay when the existing CSFB falls back, and improves CS domain service connection timeliness.

Description of drawings

FIG. 1 is a schematic diagram of a cell fallback method provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of another cell fallback method provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of another cell fallback method provided by an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a mobile terminal provided by an embodiment of the present invention.

detailed description

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

With the development of mobile communication technology, dual standby mobile terminals gradually occupy more and more proportions in the market. Moreover, with the development of the LTE technology, the communication network will also enter the LTE era. Therefore, the dual-standby mobile terminal in the LTE mode has gradually become a focus of attention.

FIG. 1 is a schematic diagram of a cell fallback method provided by an embodiment of the present invention. As shown in Figure 1, the cell fallback method includes the following steps:

101. A mobile terminal starts CSFB fallback; the mobile terminal supports a first SIM card of an LTE standard and a second SIM card of a 2G/3G standard.

Wherein, the mobile terminal is a dual-standby terminal in LTE mode, including a first SIM card supporting LTE standard and a second SIM card supporting 2G/3G standard. The first SIM card can enable the mobile terminal to reside on the LTE network and the second SIM card can enable the mobile terminal to reside on the 2G/3G network, so that the mobile terminal can be on standby in both the LTE network and the 2G/3G network. Wherein, both the first SIM card and the second SIM card can be used to provide data services and CS domain services to the mobile terminal. However, in the early stage of LTE development, the CS domain service of the first SIM card needs to be implemented in the 2G/3G network from the LTE network, which requires the first SIM card to have the CSFB function.

Before the mobile terminal starts CSFB fallback in step 101:

After the mobile terminal is powered on, the first SIM card and the second SIM card need to perform network attachment in corresponding networks respectively. The first SIM card sends a joint attachment request to the MME in the LTE network. The MME registers the PS domain of the first SIM card in the LTE network and attaches the PS domain to the LTE network. At the same time, the MME registers the CS domain of the first SIM card in the 2G /3G network to register and attach the CS domain to the 2G/3G network. Specifically, a direct SGs interface is established between the MME and the Mobile Switching Center (MSC) in the 2G/3G network, so that the joint registration function of the mobile terminal on the LTE network and the 2G/3G network can be realized.

For the PS domain under the first SIM card, the MME selects a suitable cell for the PS domain under the first SIM card as the cell to which the PS domain under the first SIM card is currently attached. For the CS domain under the first SIM card, the 2G/3G network attached to the CS domain under the first SIM card is jointly updated by the MSC or Visitor Location Register (VLR) found by the MME, and It is not actually registering the CS domain under the first SIM card to the 2G/3G network. At this time, the first SIM card can only monitor the CS domain service, but cannot execute the CS domain service.

While the first SIM card is attaching to the network, the second SIM card sends an attach request to the MSC, and the MSC registers the second SIM card in the 2G/3G network and attaches the second SIM card to the 2G/3G network. After completing the network attachment of the second SIM card, the MSC selects a suitable cell for the second SIM card as an initial cell to which the second SIM card is attached. After the first SIM card and the second SIM card are attached to the network, the first SIM card and the second SIM card can perform services carried by them on the network to which they are attached.

In practical applications, the cell to which the mobile terminal attaches when it is turned on may not be the best cell where the terminal is located. In addition, the location of the mobile terminal may change continuously. When the location of the mobile terminal is far away from the When the terminal is located, the cells selected for the first SIM card and the second SIM card when the terminal is turned on can no longer meet the service requirements of the mobile terminal. At this time, the PS domain under the first SIM card and the second SIM card need to constantly update the cell to which they are currently attached. When the second SIM card needs to perform cell update, the mobile terminal can send a cell attachment update message to the MSC through the base station corresponding to the initial cell, and the MSC can attach the second SIM card to the first cell. In this embodiment, the cell to which the second SIM card is currently attached is called the first cell.

When the first SIM card needs to perform CS domain services, the mobile terminal will receive a fallback instruction sent by the eNodeB, the base station corresponding to the cell to which the first SIM card is currently attached in the LTE network, to instruct the mobile terminal to perform CSFB fallback. In the prior art, the mobile terminal needs to search for a signal to select a suitable cell for the CS domain under the first SIM card to access the 2G/3G network, but the process of re-searching for the signal will cause a long call delay in the CS domain . In this embodiment, after the second SIM card is attached to the first cell, the first base station corresponding to the first cell sends the network information of the first cell to the mobile terminal. In this embodiment, after receiving the network information of the first cell, the mobile terminal stores the network information in the local storage unit. Wherein, the network information includes the identifier of the first cell and the identifier of the first base station.

Specifically, when the MME in the LTE network receives the CS service request, it indicates that the first SIM card needs to perform the CS domain service. In this embodiment, the first SIM card is in the LTE network. Since the CS domain service of the LTE network needs to fall back to the 2G/3G network, the MME will send an instruction to the mobile terminal to drop the CS domain service to the 2G/3G network. Fallback indication in the network. Optionally, the mobile terminal may serve as the calling party and send a CS service request to the MME, or the mobile terminal may serve as the called party, and the MME will receive the CS service request sent by the calling party through the MSC.

102. The mobile terminal acquires the network information of the first cell to which the second SIM card is currently attached from the storage unit; the network information is that after the second SIM card is attached to the first cell, the The first base station corresponding to a cell sends to the mobile terminal.

After receiving the fallback indication, the mobile terminal may acquire the network information of the first cell to which the second SIM card is currently attached from the local storage unit, and then send the network information of the first cell to the MME. Wherein, the network information of the first cell is sent to the mobile terminal by the first base station corresponding to the first cell after the second SIM card is attached to the 2G/3G network.

103. The mobile terminal sends the network information to the MME, so that the MME sends the network information to a second base station corresponding to the cell to which the first SIM card is attached, and makes the second base station according to The network information sends a handover request to the first base station.

After receiving the network information of the first cell sent by the mobile terminal, the MME sends the network information of the first cell to the second base station corresponding to the cell to which the first SIM card is currently attached. The information sends a handover request to the first base station, and applies to the first base station to drop the mobile terminal back to the target cell through the handover request. Specifically, after the MME sends the network information of the first cell to the second base station, the second base station finds the first base station according to the identifier of the first base station in the network information, and sends a handover request to the first base station. After receiving the handover request from the second base station, the first base station judges whether to allow the mobile terminal to fall back to the 2G/3G network, and sends a fallback permission response to the second base station.

104. The mobile terminal receives a handover instruction sent by the second base station; the handover instruction is sent by the first base station after receiving the handover request and allowing the CS domain under the first SIM card to fall back to the sent to the second base station when the first cell is mentioned.

Specifically, after the mobile terminal is allowed to fall back to the first cell, the mobile terminal may receive a handover instruction sent by the second base station to instruct the mobile terminal to fall back to the target cell. Specifically, after the first base station allows the mobile terminal to fall back to the first cell, it can send a fallback allowing response to the MSC, and the MSC sends the fallback allowing response to the MME, and the MME sends the fallback allowing response to the second cell after receiving the fallback allowing response. The base station sends a handover instruction, and then the second base station sends the handover instruction to the mobile terminal to instruct the mobile terminal to fall back to the first cell.

105. The mobile terminal falls back the CS domain under the first SIM card to the first cell according to the handover instruction.

After receiving the handover instruction, the mobile terminal can fall back to the first cell according to the handover instruction. After the mobile terminal falls back to the first cell, a CS domain connection is established between the mobile terminal and the first base station, and the CS domain service in the first SIM card can be continued in the first cell.

In the cell fallback method provided in this embodiment, the mobile terminal starts CSFB fallback, obtains from the storage unit the network information of the first cell to which the second SIM card is currently attached, and sends it to the MME, so that the MME sends the network information of the first cell to the MME. Give the second base station corresponding to the cell to which the first SIM card is currently attached, and make the second base station send a switching request to the first base station corresponding to the first cell according to the network information, and the mobile terminal receives the switching instruction sent by the second base station, and The CS domain under the first SIM card is dropped back to the first cell according to the handover instruction. In this embodiment, the mobile terminal includes a first SIM card of the LTE standard and a second SIM card of the 2G/3G standard, and stores the network information of the cell to which the second SIM card is currently attached locally in the mobile terminal. When the CS domain needs to perform CSFB fallback, if the cell to which the mobile terminal is attached is not the best cell or the location of the mobile terminal changes, the cell to which the first SIM card is attached in the 2G/3G network cannot meet the service requirements when it is turned on. When required, the mobile terminal can directly obtain the network information of the cell to which the second SIM card is currently attached locally, and when the base station corresponding to the cell to which the second SIM card is currently attached allows the mobile terminal to fall back, directly transfer the network information under the first SIM card to The CS domain falls back to the cell currently attached to the second SIM card, so that the CS domain services of the first SIM card can be continued, so that the mobile terminal does not need to re-search for the target cell for the CS domain under the first SIM, which overcomes the existing CSFB fallback Sometimes there is a problem of long call delay, and the timeliness of CS domain service connection is improved.

Fig. 2 is a schematic diagram of another cell fallback method provided by an embodiment of the present invention. As shown in Figure 2, the method includes the following steps:

201. The mobile terminal performs network attachment.

Wherein, the mobile terminal is a dual-standby terminal in LTE mode, including a first SIM card supporting LTE standard and a second SIM card supporting 2G/3G standard. The first SIM card can enable the mobile terminal to reside on the LTE network and the second SIM card can enable the mobile terminal to reside on the 2G/3G network, so that the mobile terminal can be on standby in both the LTE network and the 2G/3G network. Both the first SIM card and the second SIM card can provide data services and CS domain services to the mobile terminal. However, in the early stage of LTE development, the CS domain service of the first SIM card needs to be implemented in the 2G/3G network from the LTE network, which requires the first SIM card to have the CSFB function.

After the mobile terminal is powered on, the first SIM card and the second SIM card need to perform network attachment in corresponding networks respectively. The first SIM card sends a joint attachment request to the MME in the LTE network. The MME registers the PS domain of the first SIM card in the LTE network and attaches the PS domain to the LTE network. At the same time, the MME registers the CS domain of the first SIM card in the 2G /3G network to register, and attach the CS domain of the first SIM card to the 2G/3G network. Regarding the process of performing network attachment between the first SIM card and the second SIM card, reference may be made to the relevant content in the foregoing embodiments, and details are not repeated here.

It needs to be explained here that the 2G/3G network to which the CS domain under the first SIM card is attached is the joint location update performed by the MSC or VLR found by the MME, and it is not the real registration of the CS domain under the first SIM card to the 2G network. /3G network. Here, the first SIM card can monitor the CS domain service, but cannot execute the CS domain service.

In practical applications, the cell to which the mobile terminal attaches when it is turned on may not be the best cell where the terminal is located. In addition, the location of the mobile terminal may change continuously. When the location of the mobile terminal is far away from the When the terminal is located, the cells selected for the first SIM card and the second SIM card when the terminal is turned on can no longer meet the service requirements of the mobile terminal. At this time, the PS domain under the first SIM card and the second SIM card need to constantly update the cell to which they are currently attached. When the second SIM card needs to perform cell update, the mobile terminal can send a cell attachment update message to the MSC through the base station corresponding to the initial cell, and the MSC can finally attach the second SIM card to the current first cell.

202. The mobile terminal sends a CS service request to the eNodeB.

In this embodiment, the mobile terminal may serve as a calling terminal and send a CS service request through the first SIM card. Specifically, the mobile terminal sends a CS service request to the eNodeB corresponding to the cell to which the first SIM card is currently attached, so as to request the CS domain service on the first SIM card.

203. The eNodeB sends a CS service request to the MME.

204. The MME sends a fallback indication to the eNodeB.

After receiving the CS service request, since the first SIM card is in the LTE standard, the CS domain service under the first SIM card must fall back to the 2G/3G network for processing, and the MME sends a fallback instruction to the eNodeB. The fallback instruction is used to indicate that the CS domain service is dropped to the 2G/3G network, and the CS domain service is processed in the 2G/3G network.

205. The eNodeB sends the fallback indication to the mobile terminal.

206. The mobile terminal acquires network information of the first cell to which the second SIM card is currently attached.

In this embodiment, after the second SIM card is attached to the first cell, the first base station corresponding to the first cell sends the network information of the first cell to the mobile terminal. In this embodiment, after receiving the network information of the first cell, the mobile terminal stores the network information in the local storage unit. Wherein, the network information includes the identifier of the first cell and the identifier of the first base station. Further, after receiving the fallback instruction, the mobile terminal directly acquires the network information of the first cell to which the second SIM card is currently attached from the local storage unit.

207. The mobile terminal sends network information to the eNodeB.

208. The eNodeB sends the network information to the MME.

209. The MME sends the network information to the MSC2.

In this embodiment, when the first SIM card performs network attachment in step 201, the mobile switching center corresponding to the 2G/3G network to which the CS domain in the first ISM card is attached is MSC2.

210. MSC2 sends a handover request to MSC1.

According to the received network information, MSC2 can query the mobile switching center MSC1 of the network where the first cell is located. MSC2 sends a handover request to MSC1 to apply for dropping the mobile terminal back to the first cell. In this embodiment, the handover request includes network information of the first cell. Wherein, the network information of the first cell includes an identifier of the first cell and an identifier of the first base station.

It should be noted here that when the first SIM card is attached to the network, MSC2 and MSC1 corresponding to the 2G/3G network to which the CS domain in the first SIM card is attached are the same MSC, or may not be different MSCs.

211. MSC1 sends a handover request to the first base station.

After receiving the handover request, MSC1 sends a handover request to the first base station according to the identifier of the first base station carried in the network information, and applies for dropping the mobile terminal back to the first cell.

212. The first base station sends a fallback permission response to MSC1.

After receiving the handover request, the first base station may determine whether to allow the mobile terminal to fall back. If the mobile terminal is allowed to fall back to the first cell, the first base station returns a fallback permission response to MSC1.

213. MSC1 sends a fallback permission response to MSC2.

After receiving the fallback permission response, MSC1 forwards the fallback permission response to MSC2 corresponding to the 2G/3G network to which the first SIM card is attached.

214. The MSC2 sends a fallback permission response to the MME.

After receiving the Fallback Allowed Response, MSC2 forwards the Fallback Allowed Response to the MME.

215. The MME sends a fallback allow response to the eNodeB.

216. The eNodeB switches the mobile terminal to the first base station.

After receiving the fallback permission response, the eNodeB can learn that the first base station allows the mobile terminal to fall back to the first cell, and the eNodeB handovers the mobile terminal to the first base station.

217. The eNodeB sends the handover instruction to the mobile terminal.

After completing the network handover, the eNodeB sends a handover instruction to the mobile terminal, instructing the mobile terminal to fall back to the first cell.

218. The mobile terminal falls back to the first cell, and establishes a CS domain service in the first cell.

After receiving the handover instruction, the mobile terminal falls back to the first cell according to the handover instruction, and establishes a CS domain service in the first cell.

In this embodiment, the mobile terminal includes a first SIM card of the LTE standard and a second SIM card of the 2G/3G standard, and stores the network information of the first cell to which the second SIM card is currently attached locally in the mobile terminal. When the first SIM When the CS domain under the card needs to perform CSFB fallback, if the cell that the mobile terminal was attached to before is not the best cell or the location of the mobile terminal changes, the cell that the first SIM card is attached to in the 2G/3G network when it is powered on When the service requirements cannot be met, the mobile terminal can directly obtain the network information of the cell to which the second SIM card is currently attached locally, and when the base station corresponding to the cell to which the second SIM card is currently attached allows the mobile terminal to fall back, the first SIM The CS domain under the card falls back to the cell currently attached to the second SIM card, so that the CS domain service of the first SIM card can be continued, so that the mobile terminal does not need to search for the target cell again for the CS domain under the first SIM card, which overcomes the It solves the problem of long call delay when the existing CSFB falls back, and improves the timeliness of service connection in the CS domain.

Fig. 3 is a schematic diagram of another cell fallback method provided by an embodiment of the present invention. As shown in Figure 3, the method includes the following steps:

301. The mobile terminal performs network attachment.

For step 300, reference may be made to the description of related content in the foregoing embodiments, and details are not repeated here.

302. The MSC2 sends a CS service request to the MME.

The mobile terminal in this embodiment can serve as the called terminal. Other terminals may send a CS service request to the first SIM card. At this time, MSC2 in the 2G/3G network sends a CS service request to the MME in the LTE network.

303. The MME sends a fallback indication to the eNodeB.

Since the CS domain of the first SIM card needs to fall back to the 2G/3G network, after receiving the CS service request, the MME needs to send a fallback instruction to the eNodeB. Wherein, the eNodeB is a base station corresponding to a cell to which the first SIM card is attached.

304. The eNodeB sends the fallback indication to the mobile terminal.

After receiving the fallback indication, the eNodeB sends the fallback indication to the mobile terminal, so as to inform the mobile terminal to perform fallback.

305. The mobile terminal acquires network information of the first cell to which the second SIM card is currently attached.

306. The mobile terminal sends network information to the eNodeB.

307. The eNodeB sends network information to the MME.

308. The MME sends the network information to the MSC2.

309. MSC2 sends a handover request to MSC1.

310. MSC1 sends a handover request to the first base station.

311. The first base station sends a fallback permission response to MSC1.

312. MSC1 sends a fallback permission response to MSC2.

313. The MSC2 sends a fallback permission response to the MME.

314. The MME sends a fallback allow response to the eNodeB.

315. The eNodeB switches the mobile terminal to the first base station.

316. The eNodeB sends the handover instruction to the mobile terminal.

317. The mobile terminal falls back to the first cell, and establishes a CS domain service in the first cell.

For the above steps 305 to 317, reference may be made to the relevant content of steps 206 to 218 in the above example, and details will not be repeated here.

It should be noted here that when the first SIM card is attached to the network, MSC2 and MSC1 corresponding to the 2G/3G network to which the CS domain in the first SIM card is attached are the same MSC, or may not be different MSCs.

In this embodiment, the mobile terminal includes a first SIM card of the LTE standard and a second SIM card of the 2G/3G standard, and stores the network information of the first cell to which the second SIM card is currently attached locally in the mobile terminal. When the mobile terminal needs When performing CSFB fallback, if the cell to which the mobile terminal is attached when it is powered on is not the best cell or the location of the mobile terminal changes, the cell in the 2G/3G network to which the CS domain under the first SIM card is powered on cannot When the service requirements are met, the mobile terminal can directly obtain locally the network information of the cell to which the second SIM card is currently attached, and when the base station corresponding to the cell to which the second SIM card is currently attached allows the CS domain under the first SIM card to fall back, Directly drop the CS domain under the first SIM card to the cell currently attached to the second SIM card, so that the CS domain service of the first SIM card can be continued, so that the mobile terminal does not need to search for the target cell again, which overcomes the existing CSFB There is a problem of long call delay during fallback, which improves the timeliness of CS domain service connection.

FIG. 4 is a schematic structural diagram of a mobile terminal provided by an embodiment of the present invention. As shown in FIG. 4 , the mobile terminal includes: a starting module 40 , an acquiring module 41 , a sending module 42 , a receiving module 43 and a fallback module 44 .

Wherein, the mobile terminal is a dual standby terminal, and the mobile terminal is provided with a first SIM card 45 of LTE standard and a second SIM card 46 of 2G/3G standard. The first SIM card 45 can make the mobile terminal reside in the LTE network and the second SIM card 46 can make the mobile terminal reside in the 2G/3G network, so that the mobile terminal can be on standby in both the LTE network and the 2G/3G network. Both the first SIM card 45 and the second SIM card 46 can provide data services and CS domain services to the mobile terminal. However, in the early stage of LTE development, the CS domain service of the first SIM card 45 needs to be implemented in the 2G/3G network from the LTE network, which requires the first SIM card 45 to have the CSFB function.

In this embodiment, the mobile terminal further includes: a first attaching module 47 and a second attaching module 48 .

After the mobile terminal is powered on, the first attachment module 47 is configured to send a joint attachment request to the MME, so that the MME attaches the packet switched PS domain of the first SIM card 45 to the LTE network and attaches the The CS domain of the first SIM card 45 is attached in the 2G/3G network. The second attach module 48 is configured to send the attach request to the mobile switching center in the 2G/3G network at the same time when the first attach module 48 sends the attach request to the MME, so that the mobile switching center sends the attach request to the mobile switching center The second SIM card 46 is attached to the 2G/3G network.

In this embodiment, for the first SIM card 45, the MME selects a suitable cell for the PS domain under the first SIM card 45 as the cell to which the PS domain under the first SIM card 45 is currently attached. For the CS domain under the first SIM card, the 2G/3G network to which the CS domain under the first SIM card 45 is attached is the joint location update performed by the MSC or VLR found by the MME, and does not actually update the location of the first SIM card 45. Register the CS domain under the 2G/3G network. At this time, the first SIM card 45 can only monitor the CS domain service, but cannot execute the CS domain service.

While the first SIM card 45 is attaching to the network, the second SIM card 46 sends an attachment request to the MSC, and the MSC registers the second SIM card 46 in the 2G/3G network, and attaches the second SIM card 46 to the 2G/3G network. in the network. For the second SIM card 46, the MSC selects a suitable cell for the second SIM card 46 as the initial cell to which the second SIM card 46 is attached.

In practical applications, the cell to which the mobile terminal was attached may not be the best cell, and the location of the mobile terminal may change continuously. , the cells selected for the first SIM card 45 and the second SIM card 46 at the time of starting up can no longer meet the service requirements of the mobile terminal. At this time, the PS domain under the first SIM card 45 and the second SIM card 46 need to constantly update the cell to which they are currently attached.

In this embodiment, the mobile terminal further includes: a cell update module 49 and a storage unit 50 .

When the second SIM card 46 needs to perform cell update, the cell update module 49 can send a cell attachment update message to the MSC through the base station corresponding to the initial cell, and the MSC can reattach the second SIM card 46 to the first cell. In this embodiment, the cell to which the second SIM card 46 is currently attached is referred to as the first cell.

For the CS domain under the first SIM card 45, only when the CSFB fallback is sent, the CS domain under the first SIM card 45 needs to perform cell attachment again. In this embodiment, the cell to which the second SIM card 46 is currently attached is called the first cell.

Further, after the second SIM card 46 attaches to the first cell, the first base station corresponding to the first cell sends the network information of the first cell to the mobile terminal. In this embodiment, after receiving the network information of the first cell, the mobile terminal stores the network information in the storage unit 50 . Wherein, the network information includes the identifier of the first cell and the identifier of the first base station.

In this embodiment, the mobile terminal can start the CSFB fallback through the starting module 40 . When the MME in the LTE network receives the CS service request, it means that the first SIM card 45 needs to perform the CS domain service. Since the first SIM card 45 is in the LTE network, the CS domain service of the first SIM card 45 needs to fall back to the 2G/3G network.

When the mobile terminal acts as the calling side, the activation module 40 can send a CS service request to the MME through the eNodeB, the second base station corresponding to the cell to which the first SIM card 45 is currently attached. After the MME receives the CS service request, it will send the CS service request to the The starting module 40 sends a fallback instruction for instructing to drop the CS domain service to the 2G/3G network. Optionally, when the mobile terminal is the called party, when other mobile terminals can initiate a CS service request to the MME in the LTE network to which the first SIM card 45 in this embodiment is attached through the MSC, after receiving the CS service request , the MME sends a fallback indication to the starting module 40 for instructing the CS domain service to fall back to the 2G/3G network.

After the starting module 40 starts the CSFB fallback, the obtaining module 41 obtains the network information of the first standard cell to which the second SIM card 46 is currently attached from the storage unit 49 . After the acquiring module 41 acquires the network information, the sending module 42 sends the network information of the first cell to the MME, and the MME sends the network information of the first cell to the second base station corresponding to the cell to which the first SIM card 45 is currently attached, The second base station sends a handover request to the first base station according to the network information, so as to apply for dropping the mobile terminal back to the first cell. Specifically, after the MME sends the network information of the first cell to the second base station, the second base station finds the first base station according to the identifier of the first base station in the network information, and sends a handover request to the first base station. After receiving the handover request, the first base station judges whether to allow the CS domain under the first SIM card to fall back to the 2G/3G network, and sends a fallback permission response to the second base station.

If the CS domain in the first SIM card 45 has been attached in the 2G/3G network, the first base station allows the mobile terminal to fall back to the first cell. When the first base station allows the fallback of the CS domain under the first SIM card to the first cell, it can send a fallback permission response to the MSC, and the MSC sends the fallback permission response to the MME, and the MME receives the fallback permission response , sending a handover instruction to the second base station, and then the second base station sends the handover instruction to the receiving module 43 to instruct the mobile terminal to drop the CS domain under the first SIM card back to the first cell.

After the receiving module 43 receives the handover instruction, the fallback module 44 may fallback the CS domain under the first SIM card to the first cell according to the handover instruction. After the CS domain under the first SIM card falls back to the first cell, a CS domain connection is established between the mobile terminal and the first base station, and the CS domain service in the first SIM card 45 can be continued in the first cell.

The mobile terminal provided in this embodiment, when starting CSFB fallback, obtains from the storage unit the network information of the first cell to which the second SIM card is currently attached and sends it to the MME, so that the MME sends the network information of the first cell to the The second base station corresponding to the cell to which the first SIM card is currently attached, and the second base station sends a handover request to the first base station corresponding to the first cell according to the network information, and the mobile terminal receives the handover instruction sent by the second base station, and according to the The handover instructs to drop the CS domain under the first SIM card back to the first cell. In this embodiment, the mobile terminal supports the first SIM card of the LTE standard and the second SIM card of the 2G/3G standard, and stores the network information of the cell to which the second SIM card is attached locally in the mobile terminal. When the mobile terminal needs to perform CSFB fallback , because the cell to which the mobile terminal attaches when it is turned on may not be the best cell, or the cell to which the first SIM card is attached in the 2G/3G network cannot meet the service requirements when the mobile terminal is turned on due to a change in the location of the mobile terminal, the mobile terminal The network information of the cell to which the second SIM card is currently attached can be obtained directly locally, and when the base station corresponding to the cell to which the second SIM card is currently attached allows the mobile terminal to fall back, the CS domain under the first SIM card is directly dropped to the second The second SIM card is currently attached to the cell, so that the CS domain service of the first SIM card can be continued, so that the mobile terminal does not need to re-search for the target cell for the CS domain under the first SIM card, which overcomes the existing calls when the existing CSFB falls back The problem of long delay can improve the timeliness of CS domain service connection.

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

Claims (10)

1. A cell fallback method, characterized in that, comprising: The mobile terminal starts CSFB fallback, and the mobile terminal includes a first SIM card supporting the LTE standard and a second SIM card supporting the 2G/3G standard; the PS domain of the first SIM card is attached to the LTE network, and the CS domain is attached to the 2G /3G network; at the same time, the second SIM card is attached to a 2G/3G network; the first SIM card and the second SIM card carry out their respective services on the attached network; The mobile terminal acquires the network information of the first cell to which the second SIM card is currently attached from the storage unit; the network information is that the second SIM card is attached to the first cell by the first cell The corresponding first base station sends to the mobile terminal; The mobile terminal sends the network information to a mobility management entity MME, so that the MME sends the network information to a second base station corresponding to the cell to which the first SIM card is currently attached, and makes the second The base station sends a handover request to the first base station according to the network information; The mobile terminal receives the handover instruction sent by the second base station; the handover instruction is sent by the first base station after receiving the handover request and allowing the circuit switched CS domain under the first SIM card to fall back to the sent to the second base station when the first cell is mentioned; The mobile terminal falls back the CS domain under the first SIM card to the first cell according to the handover instruction. 2. The cell fallback method according to claim 1, wherein said mobile terminal starting CSFB fallback comprises: The mobile terminal sends a CS service request to the MME; The mobile terminal receives the fallback instruction sent by the MME for instructing to fallback the CS domain service to the 2G/3G network. 3. The cell fallback method according to claim 2, wherein before the mobile terminal sends the CS service request to the MME, further comprising: The mobile terminal is turned on and powered on; The mobile terminal sends a joint attach request to the MME, so that the MME attaches the packet switched PS domain of the first SIM card to the LTE network and attaches the CS domain of the first SIM card to the 2G/ In 3G network; The mobile terminal sends an attach request to a mobile switching center MSC in the 2G/3G network, so that the MSC attaches the second SIM card to an initial cell of the 2G/3G network. 4. The cell fallback method according to claim 3, wherein the mobile terminal sends an attachment request to a mobile switching center in the 2G/3G network, so that the mobile switching center attaches the second SIM card After the initial cell of the 2G/3G network, it also includes: The mobile terminal sends an attached cell change message to the MME through the base station corresponding to the initial cell, so that the MME attaches the second SIM card to the first cell according to the attached cell change message; receiving the network information sent by the first base station corresponding to the first cell; The mobile terminal stores the network information in the storage unit. The method for cell fallback according to any one of claims 1-4, wherein the network information includes: an identifier of the first cell and an identifier of the first base station. 6. A mobile terminal, characterized in that, comprising: Start module, be used for starting CSFB to fall back; An acquisition module, configured to acquire the network information of the first cell to which the second SIM card is currently attached from the storage unit; the network information is that after the second SIM card is attached to the first cell, the sent by the first base station corresponding to a cell to the mobile terminal; A sending module, configured to send the network information to an MME, so that the MME sends the network information to a second base station corresponding to a cell to which the first SIM card is attached, and makes the second base station transmit the network information according to the network information. sending a handover request to the first base station; A receiving module, configured to receive a handover instruction sent by the second base station; the handover instruction is sent by the first base station after receiving the handover request and allowing the CS domain under the first SIM card to fall back to the sent to the second base station in the first cell; A fallback module, configured to fall back the CS domain under the first SIM card to the first cell according to the handover instruction; Wherein, the mobile terminal includes the first SIM card supporting the LTE standard and the second SIM card supporting the 2G/3G standard; the PS domain of the first SIM card is attached to the LTE network, and the CS domain is attached to the 2G /3G network; at the same time, the second SIM card is attached to a 2G/3G network; the first SIM card and the second SIM card perform services carried by them on the attached network. 7. The mobile terminal according to claim 6, wherein the activation module is specifically configured to send a CS service request to the MME, and receive the fallback instruction sent by the MME. 8. The mobile terminal according to claim 7, further comprising: A first attach module, configured to send a joint attach request to the MME, so that the MME attaches the PS domain of the first SIM card to the LTE network and attaches the CS domain of the first SIM card In the initial cell of the 2G/3G network; The second attaching module is configured to send an attach request to a mobile switching center MSC in the 2G/3G network, so that the MSC attaches the second SIM card to the 2G/3G network. 9. The mobile terminal according to claim 8, further comprising: A cell change module, configured to send an attach cell change message to the MME through the base station corresponding to the initial cell, so that the MME attaches the second SIM card to the first cell according to the attach cell change message ; A storage unit, configured to receive and store the network information sent by the first base station corresponding to the first cell. 10. The mobile terminal according to any one of claims 6-9, wherein the network information includes: an identifier of the first cell and an identifier of the first base station.