WO2018171153A1

WO2018171153A1 - Method and device for handling anomaly occurring during circuit switched fallback operation, and user equipment

Info

Publication number: WO2018171153A1
Application number: PCT/CN2017/103363
Authority: WO
Inventors: 王旭康
Original assignee: 广东欧珀移动通信有限公司
Priority date: 2017-03-20
Filing date: 2017-09-26
Publication date: 2018-09-27
Also published as: CN107040967A

Abstract

Disclosed are a method and device for handling an anomaly occurring during a circuit switched fallback operation, and a user equipment unit. Upon occurrence of a network anomaly during a circuit switched fallback operation, a call-receiving UE unit searches, among respective second RAT cells, and according to quality of a call, for a target cell so as to be redirected from a registered first RAT cell to a second RAT cell to continue the call, such that a registration procedure can be executed in the target cell to proceed with the call. The present invention solves a technical problem in the prior art in which it is unable to conduct a call upon occurrence of a network anomaly during a circuit switched fallback operation.

Description

Circuit domain fallback exception processing method, device and user equipment

Cross-reference to related applications

This application claims the priority of the Chinese Patent Application No. "201710166001.7" filed on March 20, 2017 by the Guangdong Opal Mobile Communications Co., Ltd., entitled "Circuit Domain Fallback Exception Handling Method, Apparatus and User Equipment".

Technical field

The present invention relates to the field of communications technologies, and in particular, to a circuit domain fallback exception processing method, apparatus, and user equipment.

Background technique

The Circuit Switched Fallback (CSFB) is a technology for providing voice services to the user equipment when the user equipment is attached to the Long Term Evolution (LTE) network. The circuit domain fallback is mainly used for the LTE network. The user equipment in the middle can initiate a call and receive the call, and can correctly process the packet switching (PS) PS service that the terminal is performing in the LTE network.

In the circuit domain fallback process, for the called user equipment (UE), it is necessary to redirect from the LTE cell to the Global System for Mobile Communication (GSM) third-generation partnership program (3rd Generation). Under the Partnership Project, 3GPP), the call can be connected. Specifically, when redirecting, the called UE needs to perform measurement to generate a measurement report, so that the base station determines the cell to which the cell is redirected based on the measurement report.

However, in the prior art, such a measurement-based redirection process takes a long time, resulting in a timeout. In this case, the network side cannot specify the cell frequency point to which the UE is redirected, so that the cell configuration is abnormal, and the called UE cannot fall back to the Circuit Switched (CS) domain to perform voice service.

Summary of the invention

The object of the present invention is to solve at least one of the above technical problems to some extent.

Therefore, the present invention provides a circuit domain fallback exception processing method, which solves the technical problem that the called UE cannot fall back to the CS domain to perform voice service in the case where an abnormality occurs in the prior art.

The invention provides a circuit domain fallback exception processing device.

The invention proposes a UE.

The present invention proposes another UE.

The present invention provides a computer program product.

The present invention provides a computer readable storage medium.

The first aspect of the present invention provides a circuit domain fallback exception processing method, where the exception processing is performed by a called UE, and includes the following steps:

During the circuit domain fallback, a network anomaly occurs, wherein the circuit domain fallback procedure is used to redirect from the registered first radio access technology RAT cell to the second RAT cell to perform the call;

Searching for a target cell in each second RAT cell according to call quality;

Performing a registration procedure at the target cell to perform the call at the target cell.

The circuit domain fallback exception processing method of the embodiment of the present invention, when the network abnormality occurs through the circuit domain fallback process, in order to enable the called UE to be redirected from the registered first radio access technology RAT cell to the second RAT cell connection In the call, the UE searches for the target cell in each second RAT cell according to the call quality, and then performs a registration process in the target cell, thereby performing the call, which solves the problem in the prior art that if a network abnormality occurs in the circuit domain fallback process, The technical issue of making a call.

The second aspect of the present invention provides a circuit domain fallback exception processing apparatus, where the exception processing is applied to a called UE, including:

a detecting module, configured to cause a network abnormality during a circuit domain fallback process, wherein the circuit domain fallback process is used to redirect from the registered first radio access technology RAT cell to the second RAT cell to perform the call;

a searching module, configured to search for a target cell in each second RAT cell according to call quality;

a calling module, configured to perform a registration process on the target cell to perform the call in the target cell.

The circuit domain fallback exception processing apparatus of the embodiment of the present invention, when the network abnormality occurs in the circuit domain fallback process, in order to enable the called UE to be redirected from the registered first radio access technology RAT cell to the second RAT cell connection In the call, the UE searches for the target cell in each second RAT cell according to the call quality, and then performs a registration process in the target cell, thereby performing the call, which solves the problem in the prior art that if a network abnormality occurs in the circuit domain fallback process, The technical issue of making a call.

A third aspect of the present invention provides a UE, including the circuit domain fallback exception processing apparatus according to the second aspect of the present invention.

When the UE in the embodiment of the present invention experiences a network abnormality through the circuit domain fallback process, in order to enable the called UE to redirect from the registered first radio access technology RAT cell to the second RAT cell to connect the call, the UE is configured according to the UE. The call quality is searched for in the second RAT cell, and the registration process is performed in the target cell, so that the call is performed, and the technical problem that the call cannot be made if the network abnormality occurs in the circuit domain fallback process in the prior art is solved. .

A fourth aspect of the present invention proposes another UE comprising one or more of the following components: a housing and a processor, a memory located in the housing, wherein the processor reads the memory by reading the memory Executable code Running a program corresponding to the executable program code for performing the following steps:

Searching for a target cell in each second RAT cell according to call quality;

The embodiment of the fifth aspect of the present invention further provides a computer program product. When the instructions in the computer program product are executed by the processor, the circuit domain fallback exception processing method according to the first aspect embodiment is implemented.

A sixth aspect of the present invention further provides a computer readable storage medium having stored thereon a computer program, wherein when the instructions in the storage medium are executed by a processor of the user equipment, the circuit as described in the first aspect embodiment is implemented Domain fallback exception handling method.

The additional aspects and advantages of the invention will be set forth in part in the description which follows.

DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

1 is a flow chart of a circuit domain fallback exception processing method according to an embodiment of the present invention;

2 is a signaling interaction diagram of a circuit domain fallback exception processing method according to another embodiment of the present invention;

3 is a schematic structural diagram of a circuit domain fallback exception processing apparatus according to an embodiment of the present invention;

4 is a schematic structural diagram of another circuit domain fallback exception processing apparatus according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a user equipment according to another embodiment of the present invention.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

Wireless communication networks are widely deployed to provide things such as voice, video, packet data, messaging, broadcasts, and the like. Various communication content. The UE may be located within the coverage of multiple wireless networks, which may support different communication services, and may select an appropriate wireless network to serve the UE based on one or more criteria. The circuit domain fallback is a technology for providing a voice service to a user equipment when the user equipment is attached to the LTE network. The circuit domain fallback exception processing method, apparatus, and user equipment according to the embodiment of the present invention are described below with reference to the accompanying drawings.

The techniques described herein may relate to various wireless communication networks, such as Code Division Multiple Access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA). Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier FDMA (SC-FDMA), and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement a radio access technology (RAT) such as Universal Terrestrial Radio Access (UTRA), cdma2000, or the like. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. CDMA 2000 covers the IS-2000, IS-95, and IS-856 standards. IS-2000 is also known as 1x wireless transmission technology (1xRTT), CDMA2000 1X, and the like. A TDMA network may implement a RAT such as Global System for Mobile Communications (GSM), Enhanced Data Rate GSM Evolution (EDGE), or GSM/EDGE Radio Access Network (GERAN). The OFDMA network can implement such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM.RTM Such as RAT. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). Cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein may be used in the wireless networks and RATs referred to above as well as other wireless networks and RATs.

FIG. 1 is a flowchart of a circuit domain fallback exception processing method according to an embodiment of the present invention. The method provided by this embodiment may be performed by a called UE. The UE is originally registered in the first RAT cell, and in order to make a call, it needs to fall back to the CS domain and register in the second RAT cell. The first RAT includes Long Term Evolution (LTE). The second RAT includes at least one of code division multiple access CDMA, global mobile system GSM, and universal mobile telecommunications system UMTS.

A UE may be stationary or mobile, and may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, and the like. The UE may be a cellular telephone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless telephone, a wireless local loop (WLL) station, and the like.

Specifically, as shown in FIG. 1, the method includes:

In step 101, during the circuit domain fallback, a network abnormality occurs.

The circuit domain fallback procedure is used to redirect from the registered first RAT cell to the second RAT cell to perform the call.

Specifically, in the process of the circuit domain fallback, the UE receives the Radio Resource Control (RRC) connection release message, and the RRC connection release message does not include the radio resource configuration information, for example, the frequency point is not specified. In general, in the RRC Connection Release message, the wireless configuration information should be specified. When the wireless configuration information is not included in the received RRC connection release message, the configuration abnormality occurs, causing the attempted call to fail. In the prior art, the UE will return to the first RAT cell. In order to improve the call completion rate, in the embodiment of the present invention, the UE actively searches for the target cell and then registers with the target cell when an abnormality occurs, thereby connecting the call. For specific implementation, refer to the related description of the subsequent steps.

Step 102: Search for a target cell in each second RAT cell according to the call quality.

Specifically, in the process of the UE actively searching for the target cell, the required target cell may be selected according to the call quality. The call quality of the target cell should be optimal or acceptable in each of the second RAT cells.

In order to be able to query the appropriate target cell, as a possible implementation manner, the UE queries, in each second RAT cell, a cell whose location area identifier LAI is equal to the tracking area identifier TAI of the first RAT cell. If the cell with the TAI equal to the TAI of the first RAT cell is queried, the queried cell is used as the target cell. Optionally, when the cell is queried, each second RAT cell recorded in the frequency point database may be first obtained, and then, according to the description of the frequency point database, the cell with the TAI equal to the TAI of the first RAT cell is queried. Here the frequency point database is generated based on the second RAT cell that has successfully performed the call.

Further, if the cell with the LAI equal to the TAI of the first RAT cell is not queried, the second RAT cell with the strongest search signal strength is used as the target cell.

Specifically, as a possible specific implementation manner of this step, when searching for a target cell, the following steps may be performed:

First, the UE looks up the second RAT cell whose LAI is equal to the TAI of the first RAT cell from the frequency point database. Since the call is continued in such a cell, the quality of the call can be guaranteed, and the registration is initiated on the second RAT cell that is queried this time.

Secondly, if the second RAT cell with the LAI equal to the TAI of the first RAT cell is not queried in the frequency point database, the cell with the strongest signal quality is searched in the frequency point database as the target cell.

Furthermore, if there is no stored frequency point in the frequency point database, the UE may initiate a search for the second RAT cell with the LAI equal to the TAI of the first RAT cell and having the best signal strength as the target cell.

Finally, if the call is successful, the target cell that is successful in the call will be recorded and added to the frequency point database, so that subsequent registration is initiated on the target cell to improve the call completion rate.

Step 103: Perform a registration process in the target cell to make a call.

Specifically, when the target cell is searched, a paging response message is sent to the network side, so that the registration process of the target cell is performed to establish a CS connection. Further, based on the connection, a call is made.

In this embodiment, when a network abnormality occurs through the circuit domain fallback process, in order to enable the called UE to redirect from the registered first radio access technology RAT cell to the second RAT cell to connect the call, the UE according to the call quality Searching for the target cell in each of the second RAT cells, and performing the registration process in the target cell, thereby performing the call, and solving the technical problem that the call cannot be made if the network abnormality occurs in the circuit domain fallback process in the prior art.

In order to more fully explain the method of the embodiment of the present invention, the circuit domain fallback exception processing method will be described in detail below:

2 is a signaling interaction diagram of a circuit domain fallback exception processing method according to another embodiment of the present invention. As shown in FIG. 2, the method illustrates a circuitized UE and a network side device during a circuit domain fallback exception processing. Signaling interaction between.

Specifically, the network side device involved in this embodiment includes: an evolved mobile base station (Evolved Node B, eNodeB), a service support system (BSS), and a radio network subsystem (RNS-Radio Network Subsystem). ), Mobility Management Entity (MME) and Mobile Switching Center (MSC).

The following describes the signaling interaction of the circuit domain fallback exception processing method. In the call, the UE that initiates the call is hereinafter referred to as the calling UE, and the called UE is hereinafter referred to as the called UE, as shown in FIG. 2, including :

Step 201: The called UE is attached to the LTE, and the network side of the LTE receives the paging initiated by the calling UE.

Specifically, the called UE is generally in an LTE network, and performs related processes such as attachment and location area update. After the calling UE initiates the paging, the called UE is still in the LTE network. Since the LTE network cannot perform the voice service, it needs to fall back from the PS domain to the CS domain. That is, the circuit domain needs to be dropped back to the called UE.

Step 202: The MSC sends a paging request to the MME.

Specifically, after the calling UE initiates paging, the MSC of the called UE receives the IAM incoming message. Further, in order to notify the MME of the called UE, the called UE has been called to perform information of the circuit domain loop, and the MSC of the called UE sends a paging request to the MME of the called UE according to the MME information. The paging request includes call related information such as a calling number and a location area information.

In step 203, the MME sends a CS service advertisement and a paging request to the called UE.

Specifically, the MME sends a CS service advertisement and a paging request to the called UE by using the eNodeB, where the paging request message includes an identifier of the CS domain, to indicate that the called UE needs to perform circuit domain fallback. Only after the called UE is built to complete the circuit domain fallback can the call be established to implement the voice service.

In step 204, the MME returns a service request to the MSC.

Specifically, after the MME initiates a paging request to the called UE by using the eNodeB, the MME directly returns a service request message to the MSC, and does not wait for the response of the called UE.

Step 205: After the called UE receives the CS service advertisement and the paging request, the called UE returns a Network Attached Storage (NAS) extended service request to the MME, and starts a 10s timer (T3417_EXT).

Specifically, after the called UE receives the CS service advertisement and the paging request, in response to the paging request, the called UE establishes an RRC connection by sending a NAS extended service request message.

Step 206: The MME sends an S1-AP UE context modification request with a CS fallback indicator to the eNodeB, and starts a 2s timer.

Specifically, the S1-AP UE context modification request with the CS fallback indicator sent by the MME to the eNodeB is used to notify the eNodeB that the called UE is performing circuit domain fallback, and initiates a handover or redirection process according to the configuration of the network.

Step 207, the eNodeB determines a process of starting measurement by the UE and generating a measurement report after starting the process of performing measurement-based redirection.

Specifically, after the eNodeB determines the process of starting the redirection, the eNodeB requests the called UE to start the cell measurement of the different system, and after the measurement is completed, obtains the measurement report reported by the called UE.

Step 208: In response to the S1-AP UE context modification request, the eNodeB sends an S1-AP UE context modification response to the MME.

Step 209: In an abnormal situation, when the 2s timer reaches the timing 2s, the measurement is not completed, and the MME sends an RRC release message that does not include the radio resource configuration information to the eNodeB.

Specifically, under normal circumstances, the RRC release message should include radio resource configuration information. Thereby, the UE can access the target cell according to the radio resource configuration information and enter the CS domain. However, because the timer expires, the MME considers that the connection process has not progressed, and the MME sends an RRC release message that does not include the radio resource configuration information to the eNodeB.

Step 210: The eNodeB sends the RRC release message that does not include radio resource configuration information to the called UE.

Specifically, when the UE receives the RRC release message that does not include the radio resource configuration information, the UE may not be able to access the target cell according to the configuration information, that is, a configuration exception occurs. In the prior art, the called UE returns to the PS domain, causing the call to fail. In this embodiment, the UE starts to perform the process of actively searching for the target cell, which improves the probability of success.

Step 211: The called UE searches for a target cell according to the call quality, and registers with the target cell.

Specifically, in the process that the called UE actively searches for the target cell, the required target cell may be selected according to the call quality. The call quality of the target cell should be optimal or acceptable in each of the second RAT cells.

It should be noted that the specific referenced UE may refer to the related description in the foregoing embodiment according to the call quality, and the details are not described in this embodiment.

Step 212: After the called UE registers with the target cell, the called UE returns a paging response message to the MSC.

Along with the establishment of the air interface connection, the called UE returns a paging response message to the MSC through the BSS/RNS. At the page The message should carry the LAI of the target cell.

Step 213: After receiving the paging response message of the called UE, the MSC begins to perform a process of establishing a CS domain connection, and then connects the foregoing call based on the CS domain connection.

On the core network side, if the corresponding paging response message is received within 20s after the paging request is sent, the process can still be continued. In this embodiment, the MSC can start to perform the establishment of the CS after receiving the paging response message of the UE. The process of domain connection, which in turn connects the aforementioned call based on the CS domain connection.

In order to implement the above embodiments, the present invention also provides a circuit domain fallback exception processing apparatus. FIG. 3 is a schematic structural diagram of a circuit domain fallback exception processing apparatus according to an embodiment of the present invention. As shown in FIG. : detection module 31, search module 32 and call module 33.

The detecting module 31 is configured to cause a network abnormality during the circuit domain fallback.

The circuit domain fallback procedure is used to redirect from the registered first radio access technology RAT cell to the second RAT cell for the call.

Specifically, the network abnormality herein includes: receiving an RRC connection release message during the circuit domain fallback process, where the RRC connection release message does not include radio resource configuration information.

The searching module 32 is configured to search for a target cell in each second RAT cell according to the call quality.

The calling module 33 is configured to perform a registration process on the target cell to perform the call in the target cell.

Specifically, the calling module 33 is specifically configured to: when the target cell is searched, send a paging response message to the network side; perform a registration process of the target cell to establish a CS connection; Call the call.

In this embodiment, the first RAT includes Long Term Evolution (LTE), and the second RAT includes at least one of Code Division Multiple Access (CDMA), Global System for Mobile System (GSM), and Universal Mobile Telecommunications System (UMTS).

It should be noted that the foregoing description of the circuit domain fallback exception processing method is also applicable to the circuit domain fallback exception processing apparatus of the embodiment of the present invention, and the implementation principle thereof is similar, and details are not described herein again.

In summary, the circuit domain fallback exception processing apparatus of the embodiment of the present invention, when a network abnormality occurs in the circuit domain fallback process, is configured to enable the called UE to be redirected from the registered first radio access technology RAT cell to the first The second RAT cell connects the call, and the UE searches for the target cell in each second RAT cell according to the call quality, and then performs a registration process in the target cell, thereby performing the call, and solving the prior art, if the circuit domain fallback process occurs If the network is abnormal, the technical problem of the call cannot be made.

4 is a schematic structural diagram of another circuit domain fallback exception processing apparatus according to an embodiment of the present invention, such as On the basis of FIG. 3, the search module 32 includes a query unit 321 and a first determining unit 322.

The querying unit 321 is configured to query, in each second RAT cell, a cell in which the location area identifier LAI is equal to the tracking area identifier TAI of the first RAT cell.

Specifically, the querying unit 321 is specifically configured to: acquire each second RAT cell recorded in the frequency point database, where the frequency point database is generated according to the second RAT cell that has successfully performed the call; according to the frequency point database The description is to query a cell in which the LAI is equal to the TAI of the first RAT cell.

The first determining unit 322 is configured to: if the LAI is equal to the TAI of the first RAT cell, the queried cell is used as the target cell.

Further, the search module 32 further includes: a second determining unit 323.

The second determining unit 323 is configured to: if the LAI is not equal to the TAI of the first RAT cell, search for the second RAT cell with the strongest signal strength as the target cell.

In order to implement the above embodiments, the present invention also proposes a user equipment, which includes a circuit domain fallback exception processing apparatus.

It should be noted that the foregoing description of the embodiment of the circuit domain fallback exception processing apparatus is also applicable to the user equipment of the embodiment of the present invention, and the implementation principle thereof is similar, and details are not described herein again.

In summary, the user equipment in the embodiment of the present invention, when the network abnormality occurs in the circuit domain fallback process, is configured to enable the called UE to be redirected from the registered first radio access technology RAT cell to the second RAT cell connection. In the call, the UE searches for a target cell in each second RAT cell according to the quality of the call, and then performs a registration process in the target cell to perform the call, which solves the problem in the prior art that if a network abnormality occurs in the circuit domain fallback process, Technical problem with not being able to make a call.

In order to implement the above embodiments, the present invention also proposes another user equipment, which may be stationary or mobile, and may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, and the like. The user equipment can be a cellular telephone, a personal digital assistant, a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless telephone, a wireless local loop station, and the like. FIG. 5 is a schematic structural diagram of a user equipment according to another embodiment of the present invention. As shown in FIG. 5, the user equipment 1000 includes: a housing 1100 and a memory 1111, a processor 1112, and a communication interface located in the housing 1100. Port 1113.

The processor 1111 runs a program corresponding to the executable program code by reading the executable program code stored in the memory 1112 for performing the following steps:

Searching for a target cell in each second RAT cell according to call quality;

It should be noted that the foregoing description of the method for processing the circuit domain fallback exception is also applicable to the user equipment 1000 of the embodiment of the present invention, and the implementation principle thereof is similar, and details are not described herein again.

In order to implement the above embodiments, the present invention also provides a computer program product, which implements a circuit domain fallback exception processing method as described in the foregoing method embodiments when instructions in the computer program product are executed by the processor.

In order to achieve the above embodiments, the present invention further provides a computer readable storage medium having stored thereon a computer program that implements a circuit as described in the foregoing method embodiments when instructions in the storage medium are executed by a processor of the user device Domain fallback exception handling method.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

A circuit domain fallback exception processing method is characterized in that the exception processing is performed by a called user equipment UE, and includes the following steps:

During the circuit domain fallback, a network anomaly occurs, wherein the circuit domain fallback procedure is used to redirect from the registered first radio access technology RAT cell to the second RAT cell to perform the call;

Searching for a target cell in each second RAT cell according to call quality;

Performing a registration procedure at the target cell to perform the call at the target cell.
The circuit domain fallback exception processing method according to claim 1, wherein the searching for a target cell in each of the second RAT cells according to the call quality includes:

In each of the second RAT cells, querying a cell in which the location area identifier LAI is equal to the tracking area identifier TAI of the first RAT cell;

If the cell with the TAI equal to the TAI of the first RAT cell is queried, the queried cell is used as the target cell.
The circuit domain fallback exception processing method according to claim 2, wherein after the querying the location area identifier LAI and the tracking area identifier TAI of the first RAT cell are equal, the method further includes:

If the cell with the LAI equal to the TAI of the first RAT cell is not queried, the second RAT cell with the strongest search signal strength is used as the target cell.
The circuit domain fallback exception processing method according to claim 2, wherein in each of the second RAT cells, the cell that queries the location area identifier LAI and the tracking area identifier TAI of the first RAT cell is included, including :

Acquiring each second RAT cell recorded in the frequency point database, wherein the frequency point database is generated according to the second RAT cell that has successfully performed the call;

According to the description of the frequency point database, the cell in which the LAI is equal to the TAI of the first RAT cell is queried.
The circuit domain fallback exception processing method according to claim 1, wherein the performing a registration process in the target cell to perform the call in the target cell includes:

Sending a paging response message to the network side when the target cell is searched;

Performing a registration process of the target cell to establish a circuit domain CS connection;

The call is made based on the connection.
The circuit domain fallback exception processing method according to claim 5, wherein the sending the paging response message to the network side comprises:

Sending a paging response message to the mobile switching center MSC by the service support system BSS/radio network subsystem RNS, so that the MSC performs a process of establishing a CS domain connection, where the paging response message carries the target cell LAI.
The circuit domain fallback exception processing method according to claim 1, wherein the network abnormality comprises: receiving a radio resource control RRC connection release message, the RRC connection release message during the circuit domain fallback process Radio resource configuration information is not included.
The circuit domain fallback exception processing method according to any one of claims 1 to 7, wherein

The first RAT includes Long Term Evolution (LTE);

The second RAT includes at least one of code division multiple access CDMA, global mobile system GSM, and universal mobile telecommunications system UMTS.
A circuit domain fallback exception processing apparatus, wherein the exception processing is applied to a called user equipment UE, including:

a detecting module, configured to cause a network abnormality during a circuit domain fallback process, wherein the circuit domain fallback process is used to redirect from the registered first radio access technology RAT cell to the second RAT cell to perform the call;

a searching module, configured to search for a target cell in each second RAT cell according to call quality;

a calling module, configured to perform a registration process on the target cell to perform the call in the target cell.
The circuit domain fallback exception processing apparatus according to claim 9, wherein the search module comprises:

a querying unit, configured to query, in each second RAT cell, a cell in which the location area identifier LAI is equal to the tracking area identifier TAI of the first RAT cell;

The first determining unit is configured to: if the cell with the TAI equal to the TAI of the first RAT cell is queried, use the queried cell as the target cell.
The circuit domain fallback exception processing apparatus according to claim 10, wherein the search module further comprises:

And a second determining unit, configured to: if the LAI is not equal to the TAI of the first RAT cell, the second RAT cell with the strongest signal strength is used as the target cell.
The circuit domain fallback exception processing apparatus according to claim 10, wherein the query unit is specifically configured to:

Acquiring each second RAT cell recorded in the frequency point database, wherein the frequency point database is generated according to the second RAT cell that has successfully performed the call; according to the record of the frequency point database, querying the LAI and the first RAT The cell with the same TAI of the cell.
The circuit domain fallback exception processing apparatus according to claim 9, wherein the call module is specifically configured to:

When the target cell is searched, a paging response message is sent to the network side; a registration procedure of the target cell is performed to establish a circuit domain CS connection; and the call is made based on the connection.
The circuit domain fallback exception processing apparatus according to claim 13, wherein the call module is further configured to:

Sending a paging response message to the mobile switching center MSC by the service support system BSS/radio network subsystem RNS, so that the MSC performs a process of establishing a CS domain connection, where the paging response message carries the target cell LAI.
The circuit domain fallback exception processing apparatus according to claim 9, wherein the network abnormality comprises: receiving an RRC connection release message during the circuit domain fallback process, where the RRC connection release message does not include wireless Resource configuration information.
A circuit domain fallback exception processing apparatus according to any one of claims 9-15, characterized in that

The first RAT includes Long Term Evolution (LTE);

The second RAT includes at least one of code division multiple access CDMA, global mobile system GSM, and universal mobile telecommunications system UMTS.
A user equipment, comprising the circuit domain fallback exception processing apparatus according to any one of claims 8-14.
A user equipment, comprising: one or more of: a housing and a processor, a memory located within the housing, wherein the processor reads the executable program code stored in the memory Running a program corresponding to the executable program code for performing the following steps:

During the circuit domain fallback, a network anomaly occurs, wherein the circuit domain fallback procedure is used to redirect from the registered first radio access technology RAT cell to the second RAT cell to perform the call;

Searching for a target cell in each second RAT cell according to call quality;

Performing a registration procedure at the target cell to perform the call at the target cell.
A computer program product, characterized in that the circuit domain fallback exception processing method according to any one of claims 1-8 is implemented when an instruction in the computer program product is executed by a processor.
A computer readable storage medium having stored thereon a computer program, characterized in that the circuit of any one of claims 1-8 is implemented when an instruction in the storage medium is executed by a processor of a user device Domain fallback exception handling method.