WO2014026596A1 - Method and device for searching for long-term evolution network - Google Patents

Description

 Search method and device for long-term evolution network The present application claims to be submitted to the Chinese Patent Office on September 12, 2012, the application number is 201210337562.6, and the invention name is "a method and device for searching for LTE network by terminal supporting GSM" Priority of the patent application, and the priority of the Chinese patent application filed on August 14, 2012, the Chinese Patent Office, Application No. 201210289523.3, entitled "A Search Method and Apparatus for a Long Term Evolution Network", the entire contents of which is incorporated herein by reference. It is incorporated by reference in this application. TECHNICAL FIELD The present application relates to the field of mobile communications technologies, and in particular, to a search method and apparatus for a long term evolution network. In the early stage of LTE (Long-Term Evolution) network deployment, the deployment strategy of each operator is hotspot coverage, so the coverage of the LTE network is much smaller than that of the 2G/3G network coverage, and the LTE network appears. The coverage area must have a 2G/3G network, while the 2G/3G network coverage area does not necessarily have an LTE network.

 In the case of the LTE network coverage mentioned above, when the LTE terminal roams on or off during use, the LTE terminal first searches according to the network frequency registered at the time of the last shutdown or when the network is disconnected, if the network was last shut down Or the network frequency search that is registered when the network is dropped fails, and then the LTE full-band search is performed. Since many LTE terminals support FDD and TDD modes, and there are many TDD and FDD bands, it takes a long time for LTE terminals to perform LTE full-band search. Such a search method will lengthen the time that the LTE terminal is not in the service area.

 In addition, in the case of the LTE network coverage described above, when the terminal is in the 2G/3G network, the method for the terminal to search for the LTE network is as follows: First, the user using the terminal selects the LTE network immediately through the interface of the terminal, or every 15 minutes, Searching for any one of the LTE networks for searching in 30 minutes or 60 minutes; then, the terminal outputs the result of the search to the user; finally, the user decides whether to select the LTE network. In the above method, the terminal searching for the LTE network is initiated by user setting, and therefore, the efficiency of searching for the LTE network is relatively low. SUMMARY OF THE INVENTION The embodiments of the present invention provide a method and an apparatus for a GSM-enabled terminal to search for an LTE network, so as to solve the problem that the LTE frequency band is long, the LTE terminal searches for the LTE frequency band, and the LTE terminal does not have a long service time.

 The embodiment of the present application provides a method for a GSM-enabled terminal to search for an LTE network, including:

 After searching for the GSM network, the terminal searches for the LTE frequency corresponding to the searched GSM network; the terminal searches for the retrieved LTE frequency.

The terminal synchronizes the search for the LTE network and the GSM network. An embodiment of the present application provides an apparatus for a GSM-enabled terminal to search for an LTE network, where the apparatus includes: a GSM radio frequency module: configured to: after searching for a GSM network, retrieve an LTE frequency point corresponding to the searched GSM network;

 LTE radio module: Used to search for the retrieved LTE frequency.

 The LTE radio module and the GSM radio module perform network search simultaneously; the LTE radio module performs LTE network search, and the GSM radio module performs GSM network search.

 In the embodiment of the present application, the LTE network and the GSM network are searched by using the terminal synchronization. After searching for the GSM network, the terminal searches for the LTE frequency corresponding to the searched GSM network; the terminal searches for the retrieved LTE frequency. In the embodiment of the present application, the terminal searches for the LTE network and the GSM network. When searching for the GSM network and searching for the LTE frequency corresponding to the searched GSM network, the LTE frequency corresponding to the GSM network is preferentially searched, and the search is improved. The possibility of registering LTE frequency points shortens the duration of LTE network search.

 The embodiment of the present application provides a search method and device for a long-term evolution network, which is used to solve the problem that the LTE network search is inefficient due to the LTE network search initiated by the user setting.

 Based on the above problem, the method for searching for a long term evolution network provided by the embodiment of the present application includes: determining, by a terminal in a 2G or 3G network, whether a cell ID of a current serving cell exists in a success list, where the terminal is in the The LTE network has been searched in the cell corresponding to each cell ID included in the success list;

 After determining that the cell ID of the current serving cell exists in the success list, the terminal searches for the LTE network in the current serving cell.

 The search method of the long-term evolution network provided by the embodiment of the present application saves the cell ID of the serving cell in the success list when the terminal searches for the LTE network, so that the terminal enters the terminal ID corresponding to the cell ID included in the success list. When the terminal accesses the 2G or 3G network, the terminal automatically searches for the LTE network in the cell, and does not wait for the user to initiate the search for the LTE network, thereby improving the efficiency of the LTE network search.

 The above successful list can be obtained by:

 When the terminal initiates a search for the LTE network through the user setting, if the LTE network is successfully searched, the cell ID of the serving cell when searching for the LTE network is added to the success list.

 Preferably, the success list includes a location area identifier LAI of the location area LA and a cell ID corresponding to the LAI. Correspondingly, the specific steps when determining whether the success list includes the cell ID of the current serving cell include:

 The terminal searches the success list for the cell ID corresponding to the LAI of the current LA;

 The terminal determines whether there is a cell ID of the current serving cell in the found cell ID.

When the success list includes more cell IDs, the LAI corresponding to the cell ID of the current serving cell may be first searched, and then only the cell IDs of the current serving cell in all the cell IDs corresponding to the LAI are determined, and the judgment is improved. Speed, further shortening the time for the terminal to search for the LTE network, thereby further improving the search efficiency of the LTE network Rate.

 The successful list including the LAI may be obtained by: after the terminal initiates the search for the LTE network command by the user setting, if the LTE network is successfully searched, the LAI and the serving cell of the LA are located when the LTE network is searched. The cell ID is added to the success list, and the cell ID of the serving cell is obtained as the cell ID corresponding to the LAI of the LA.

 Based on any of the foregoing embodiments, the location area identifier LAI of the location area LA and the cell ID corresponding to the LAI, the terminal determines that the cell ID of the current serving cell does not exist in the success list, and further includes the following steps. :

 The terminal checks whether the cell ID of the current serving cell exists in the candidate list, where the cell corresponding to the cell ID included in the candidate list is a neighboring cell of the cell corresponding to the cell ID included in the success list;

 After determining that the cell ID of the current serving cell exists in the candidate list, determining, by the terminal, whether the LAI of the current LA exists in the success list;

 After determining that the LAI of the current LA exists in the success list, the terminal searches for the LTE network in the current serving cell.

 Increasing the candidate list is based on the fact that the cell added to the success list can search for the LTE network, and the possibility of searching for the LTE network in the cell adjacent thereto is also high, so for the cell ID in the candidate list, As long as its corresponding LAI is also in the success list, the terminal can automatically search for the LTE network. This can reasonably improve the terminal's automatic search for LTE probability, thereby further improving the efficiency of LTE network search.

 If the cell ID of the current serving cell is in the candidate list, and the terminal searches for the LTE network in the current serving cell, the terminal deletes the cell ID of the current serving cell from the candidate list, and adds the cell ID of the current serving cell. Go to the success list and the cell ID that corresponds to the LAI of the current LA.

 Further, after the terminal adds the cell ID of the current serving cell to the success list and is the cell ID corresponding to the LAI of the current LA, the following steps may be further included:

 The terminal determines that the cell ID of the neighboring cell of the current serving cell is not included in the success list, the candidate list, or the forbidden list; the terminal adds the neighbor cell ID of the current serving cell to the candidate list.

 The foregoing prohibition list is that when the cell ID of the current serving cell is included in the candidate list and the LAI of the current LA is included in the success list, after the number of times the terminal fails to search for the LTE network in the current serving cell exceeds the threshold, the terminal will The cell ID of the serving cell is removed from the candidate list and added to the forbidden list.

The use of the forbidden list can overcome that when the terminal does not search for the LTE network at any position in the cell identified by some cell IDs included in the candidate list, the LTE can be searched in a neighboring cell of the cell. In the network, the cell ID of the neighboring cell of the cell is added to the success list, so that the cell ID of the cell of the terminal is added to the backup list, and when the terminal returns to the cell, the LTE network will not be searched. The cell ID of the cell is deleted from the backup list. If the terminal can search for the LTE network in more than one neighboring cell of the cell, it will result in The cell ID of the cell, that is, the cell ID of the cell that cannot search for the LTE network, is continuously added to the backup list, and then deleted, so that the terminal repeatedly repeats the operations of adding and deleting, thereby occupying the shortcomings of the resources of the terminal.

 In addition, using the forbidden list may also overcome when the terminal does not search for the LTE network in any location in the cell identified by some cell IDs included in the candidate list, since these cell IDs are present in the candidate list and The LAIs corresponding to the cell IDs are present in the success list, and the terminal continuously searches for the LTE network automatically in the cells identified by the cell IDs, so that the terminal power is consumed in a large amount.

 Therefore, the use of the forbidden list not only prevents the terminal resources from being wasted, but also prevents the terminal power from being unnecessarily lost.

 The embodiment of the present application further provides a search device for a long term evolution network, including:

 a determining module, configured to determine whether a cell ID of a current serving cell in which the terminal in the 2G or 3G network is located exists in a success list, where the terminal corresponds to a cell corresponding to each cell ID included in the success list Zhongdu has searched for LTE networks;

 And a processing module, configured to determine that a cell ID of the current serving cell exists in the success list, and send an instruction to the terminal to search for the LTE network.

 The above list of successes is obtained as follows:

 The processing module is further configured to: after receiving the instruction that the terminal successfully searches for the LTE network by using the user setting, and successfully searching for the LTE network, add the cell ID of the serving cell when searching for the LTE network to the success list.

 Preferably, if the success list includes the location area identifier LAI of the location area LA and the cell ID corresponding to the LAI, the determining module is further configured to search the success list for the cell ID corresponding to the LAI of the current LA, and determine that the cell ID is found. Is there a cell ID of the current serving cell in the cell ID.

 The above successful list containing LAI is obtained as follows:

 The processing module is further configured to: after receiving the instruction that the terminal initiates the search for the LTE network and successfully search for the LTE network by using the user setting, add the LAI of the LA and the cell ID of the serving cell when the LTE network is searched to the success In the list, the cell ID of the monthly cell is used as the cell ID corresponding to the LAI of the LA.

 Further, after determining that the cell ID of the current serving cell does not exist in the success list, the determining module is further configured to check whether the cell ID of the current serving cell exists in the candidate list, where the cell ID included in the candidate list corresponds to The cell is a neighboring cell of the cell corresponding to the cell ID included in the success list; and after determining that the cell ID of the current serving cell exists in the candidate list, determining whether the LAI of the current LA exists in the success list;

 The processing module is further configured to: after determining that the LAI of the current LA exists in the success list, send an instruction to the terminal to search for the LTE network.

Preferably, the processing module is further configured to: after receiving the instruction that the terminal searches for the LTE network, delete the cell ID of the current serving cell from the candidate list, and add the cell ID of the current serving cell to the success list and The cell ID corresponding to the LAI of the current LA. Further, after the cell ID of the current serving cell is added to the success list and is the cell ID corresponding to the LAI of the current LA, the processing module is further configured to determine that the cell ID of the neighboring cell of the current serving cell is not included in the success list, In the candidate list or the forbidden list, the neighbor cell ID of the current serving cell is added to the candidate list.

 Preferably, the processing module is further configured to: after receiving the number of times that the terminal fails to search for the LTE network in the current serving cell, the cell ID of the current serving cell is deleted from the candidate list, and is added to the forbidden list. The terminal never searches for an LTE network in a cell corresponding to each cell ID included in the forbidden list.

 The search device of the long-term evolution network provided by the embodiment of the present application saves the cell ID of the serving cell in the success list when the terminal searches for the LTE network, so that the terminal enters the cell corresponding to the cell ID included in the success list and When the terminal accesses the 2G or 3G network, the terminal automatically searches for the LTE network in the cell, and does not wait for the user to initiate the search for the LTE network, thereby improving the efficiency of the LTE network search.

 The embodiment of the present application further provides a terminal that accesses a 2G or 3G network, and the terminal includes any of the foregoing devices. The embodiment of the present application further provides a terminal that accesses a 2G or 3G network, and the terminal includes:

 a processor, the processor is configured to determine whether the cell ID of the current serving cell exists in the success list, where the cell corresponding to each cell ID included in the success list has searched for the LTE network; After the cell ID of the serving cell exists in the success list, the LTE network is searched for in the current serving cell.

 The terminal provided by the embodiment of the present application saves the cell ID of the serving cell in the success list when the terminal searches for the LTE network, so that the terminal enters the cell corresponding to the cell ID included in the success list and the terminal accesses 1 In the G or 3G network, the terminal automatically searches for the LTE network in the cell without waiting for the user to initiate searching for the LTE network, thereby improving the efficiency of the LTE network search.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic flowchart of a method for a GSM-enabled terminal to search for an LTE network according to an embodiment of the present disclosure; FIG. 2 is a schematic diagram of a specific method for searching for an LTE frequency corresponding to a GSM network according to an embodiment of the present application; A schematic diagram of a specific method for a terminal to perform an LTE network search according to a frequency point in an LTE frequency point list in the embodiment of the present application;

 FIG. 3B is a schematic diagram of a specific method for retrieving and searching for a LTE frequency corresponding to a GSM network before performing a LTE network search according to a frequency point in an LTE frequency point list according to an embodiment of the present application;

 4A is a schematic diagram of a specific method for a terminal to perform an LTE network search according to a frequency point in an LTE frequency point list according to an embodiment of the present application;

FIG. 4B is a diagram of a terminal searching for an LTE network according to a frequency point in an LTE frequency point list according to an embodiment of the present application; A schematic diagram of a specific method of LTE frequency points corresponding to the searched GSM network;

 FIG. 5 is a schematic flowchart of a LTE terminal network searching method according to an embodiment of the present application;

 FIG. 6 is a schematic diagram of an apparatus for searching for an LTE network by a GSM-enabled terminal according to an embodiment of the present disclosure; FIG. 7 is a flowchart of a method for searching for an LTE network according to an embodiment of the present application;

 FIG. 8 is a second flowchart of a method for searching for an LTE network according to an embodiment of the present application;

 FIG. 9 is a third flowchart of a method for searching for an LTE network according to an embodiment of the present application;

 FIG. 10 is a flowchart of adding a cell ID to an alternative list when using the LTE network search method provided by the embodiment of the present application;

 FIG. 11 is a flowchart of a search method of an LTE network according to an embodiment of the present disclosure; FIG. 12 is a schematic structural diagram of a search apparatus of an LTE network according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The solution used in the embodiments of the present application is: the terminal synchronizes the LTE network and the GSM network, and after searching for the GSM network, searches for the LTE frequency corresponding to the searched GSM network; the terminal searches for the retrieved LTE. Search by frequency. In the embodiment of the present application, the terminal synchronizes to search for the LTE network and the GSM network. When searching for the GSM network and searching for the LTE frequency corresponding to the searched GSM network, the LTE frequency corresponding to the GSM network is preferentially searched, and the search is improved. The possibility of registering LTE frequency points shortens the duration of LTE network search.

 The embodiments of the present application are further described in detail below with reference to the accompanying drawings.

 As shown in FIG. 1 , a method for a GSM-enabled terminal to search for an LTE network includes the following steps: Step 101: After searching for a GSM network, the terminal searches for an LTE frequency corresponding to the searched GSM network; 102: The terminal searches for the retrieved LTE frequency.

 The reasons for the terminal to perform network search include but are not limited to: the terminal is powered on, and the terminal is disconnected during use. The terminal searches for the LTE network and the GSM network in two ways. One is that the terminal synchronizes to search for the LTE network and the GSM network, and the other is that the terminal performs the GSM network search first, and then performs the LTE network search after the search is completed. The two search methods are described separately below.

 Method 1: Terminal synchronization searches for LTE network and GSM network

 When the terminal synchronizes to search for the LTE network and the GSM network, for the LTE network search, the terminal first performs an LTE network search according to the frequency of the last successful registration. For the GSM network search, the terminal searches according to the frequency in the GSM frequency list. GSM network.

 There are several cases in which terminal synchronization searches for LTE networks and GSM networks.

In the first case, when the terminal synchronizes to search for the LTE network and the GSM network, for the search of the LTE network, the terminal first performs an LTE network search according to the frequency of the last successful registration, and the frequency of the last successful registration of the terminal. If the search and registration are successful, it is determined whether the registered LTE frequency point is stored in the LTE frequency list, and if it is stored in the LTE frequency list, the process ends; if not stored in the LTE frequency list, the LTE frequency is updated. Point the list, and store it.

 In the second case, when the terminal synchronizes the search for the LTE network and the GSM network, the LTE network searches for the LTE network according to the frequency of the last registration success, and the LTE network is not searched. After completion, the LTE frequency corresponding to the searched GSM network is retrieved, and the retrieved corresponding LTE frequency is searched. If the LTE frequency point is not searched for the corresponding LTE frequency search retrieved for the GSM network, the LTE network is searched according to the frequency point in the LTE frequency list.

 As shown in FIG. 2, a specific method for searching for the LTE frequency corresponding to the GSM network is completed for the GSM network.

 There are two types of LTE frequencies: TDD and FDD, which are represented by System 1 and System 2, respectively. Where, if the system 1 is the TDD system, the system 2 is the FDD system; if the system 1 is the FDD system, the system 2 is the TDD system.

 After the GSM network search is completed, the search for the PLMN id information may be performed for the PLMN id in the PLMN information, and may correspond to one or more LTE frequency points, or may not have a corresponding LTE frequency point, and the PLMN id of the searched GSM network. Confirm the LTE frequency corresponding to the GSM network for recording. As shown in FIG. 2, it is assumed that the GSM network searches for three PLMN ids, wherein the PLMN id1 searches for the frequency point 3 of the system 1 and the frequency point 5 of the system 1 in the LTE frequency point, and the PLMN id2 searches for the LTE frequency point in the system 1 Frequency point 5, PLMN id3 searches for the frequency point 1 of the system 2 in the LTE frequency point; the frequency point 3 of the system 1 in the LTE frequency point searched by the GSM network, the frequency point 5 of the system 1 and the frequency point 1 of the system 2 Recording is performed, and the LTE frequency of the search record is sent to the LTE network.

 As shown in FIG. 3A, it is a specific method for the terminal to perform LTE network search according to the frequency point in the LTE frequency point list. It is assumed that the system 1 has n frequency points in the LTE network, and the system 2 has m frequency points; the LTE network is normal. The frequency search order is the system 1 frequency point 1, the system 1 frequency point 2, ..., the system 1 frequency point n, the system 2 frequency point 1, the system 2 frequency point 2, ..., the system 2 frequency point m.

 As shown in FIG. 3B, the LTE network search is performed based on the frequency of the last registration success, and the LTE network is not searched. At this time, the GSM network has searched and the LTE frequency corresponding to the searched GSM network is retrieved. .

After the GSM network search succeeds, the LTE frequency point search is performed on the retrieved LTE frequency point using the search order in FIG. 2 . When the terminal performs the LTE network search according to the frequency of the last successful registration, the LTE network is not searched, and the GSM network has completed the search, and the LTE frequency corresponding to the searched GSM network is retrieved and sent to the LTE network, and the LTE network is used. First, the corresponding LTE frequency points searched by the GSM network are searched, that is, the frequency search order of the LTE network is: system 1 frequency point 3, system 1 frequency point 5, system 2 frequency point 1, system 1 frequency Point 1, system 1 frequency point 2, .··, system 1 frequency point n, system 2 frequency point 2, system 2 frequency point 3, system 2 frequency point m. In the third case, when the terminal synchronizes to search for the LTE network and the GSM network, for the LTE network search, the terminal first performs an LTE network search according to the frequency of the last successful registration, and does not search for the LTE network, and the GSM network is not yet After the search is completed, the LTE network searches for the LTE network according to the frequency point in the LTE frequency list; before the LTE network performs the LTE network search according to the frequency point in the LTE frequency list, the GSM network search is completed, and the LTE network is currently searching. After the LTE frequency search is completed and the search is not successful, the LTE network search according to the frequency point in the LTE frequency list is temporarily stopped, and the corresponding LTE frequency search searched by the GSM network is performed, and the corresponding search in the GSM network is performed. If the LTE frequency is not searched successfully, the LTE network search is continued according to the frequency point in the LTE frequency list. The specific search method is shown in FIGS. 4A and 4B.

 As shown in FIG. 4A, in the embodiment of the present application, the terminal is performing an LTE network search according to the frequency point in the LTE frequency point list, where the terminal is in accordance with the frequency point in the LTE frequency list. To perform the search, the frequency point 4 of the system 1 is the next frequency point waiting for the search.

 As shown in FIG. 4B, the GSM network completes the search at this time, wherein the corresponding LTE frequency point searched by the GSM network is as shown in FIG. 2, that is, the GSM network searches for the frequency point 3 of the system 1 in the LTE frequency point, Frequency point 5 of 1 and frequency point 1 of system 2. After the LTE network completes the search of the frequency 1 point of the system 1, it searches for the corresponding LTE frequency point searched by the GSM network: the system 1 frequency point 5, the system 2 frequency point 1, if the corresponding LTE frequency point searched in the GSM network If the search is not successful, the LTE network continues to search for the system 1 frequency point 4, the system 1 frequency point 6, ..., the system 1 frequency point n, the system 2 frequency point 2, . . . , the system 2 frequency point m.

 In the fourth case, when the terminal synchronizes the search for the LTE network and the GSM network, the LTE network searches for the LTE network based on the frequency of the last registration success, and the LTE network is not searched, and the GSM network is not yet After the search is completed, the LTE network searches for the LTE network according to the frequency point in the LTE frequency list; when the LTE network successfully searches for the LTE network according to the frequency point in the LTE frequency list, the GSM network also completes the search, and the terminal searches according to the search. The LTE network frequency is registered, and the LTE frequency is stored in the LTE frequency list of the terminal. If the LTE frequency list is stored in the terminal, the process ends. If the LTE is not stored in the terminal, In the frequency list, the LTE frequency list is updated, and the process is ended after the update.

 Method 2: The terminal searches for the GSM network first, and searches for the LTE network after the search is completed.

 First, the GSM network search is started. When the GSM network search is completed, the corresponding LTE frequency searched by the GSM network is searched. If the corresponding LTE frequency searched in the GSM network is not searched successfully, the frequency in the LTE frequency list is used. The LTE network search is performed in the same manner as in FIG. 3, and details are not described herein again.

 Preferably, in step 102, the terminal searches for the LTE frequency point successfully and registers the LTE frequency search in the LTE network search process, and searches whether the LTE frequency point is stored in the LTE frequency point list of the terminal, if If it is stored in the LTE frequency list of the terminal, the process ends. If it is not stored in the LTE frequency list of the terminal, the LTE frequency list is updated, and the process is terminated after the update.

As shown in FIG. 5, it is a specific implementation step of the LTE terminal network searching method according to the embodiment of the present application. Step 501: Enable LTE network search.

 Step 502: Perform an LTE network search on the frequency of the last successful registration, and determine whether the frequency of the last successful registration is successful. If the search is successful, go to step 508; if the search is not successful, go to step 503; : determining whether the GSM network search is completed at this time, if the GSM network search is completed, executing step 504; if the GSM network does not complete the search, performing step 510;

 Step 504: Determine whether the GSM network searches for PLMN information, if the PLMN information is searched, step 505 is performed, and if the PLMN information is not found, step 510 is performed;

 Step 505: Determine whether the searched PLMN information has a corresponding LTE frequency point, if there is a corresponding LTE frequency point, go to step 506; if there is no corresponding LTE frequency point, go to step 510;

 Step 506: Determine whether the LTE frequency point has been searched, if the LTE frequency point has not been searched, go to step 507; if the LTE frequency point has been searched, go to step 510;

 Step 507: Perform a search at the frequency point, and determine whether the search is successful at the frequency point and register. If the frequency search succeeds and registration is performed, step 508 is performed; if the frequency search is not successful, step 510 is performed. ;

 Step 508: Determine whether the LTE frequency point of the search success and registration is in the LTE frequency list, if it is in the LTE frequency list, the process ends; if not, step 509 is performed;

 Step 509: Update the LTE frequency point list, and store, and end the process;

 Step 510: Determine whether all the frequency points of the LTE network are all searched, and if all the searches are completed, perform a search of the 3G network; if the search is not completed, perform step 511;

 Step 511: Search for the LTE network according to the frequency point in the LTE frequency list, and then perform step 512;

 Step 512: Determine whether the LTE frequency search of the LTE network search is successful and register, if the search is successful and the registration is performed, go to step 508; if the search is not successful, go to step 510;

 Step 513: Enable GSM network search;

 Step 514: Determine whether the LTE network searches for the corresponding LTE frequency point, and if the corresponding LTE frequency is searched, perform step 515; if there is no corresponding LTE frequency point that is searched, the process ends.

 Step 515: Determine whether the current LTE network has been searched. If the LTE network has completed the search, the process ends. If the LTE network has not completed the search, step 506 is performed.

 Based on any of the foregoing embodiments, the specific implementation manner of the terminal retrieving the LTE frequency corresponding to the searched GSM network may be: the terminal determines the PLMN information of the searched GSM network, and searches and searches according to the PLMN information. The GSM network corresponds to the LTE frequency. The specific implementation manner can be described in the second case of the above manner 1.

Based on the same inventive concept, a device for network search is also provided in the embodiment of the present application. The principle of solving the problem is similar to the method for searching the network in the embodiment of the present application. Therefore, the implementation of the device can be implemented by referring to the method. It will not be repeated here. As shown in FIG. 6 , an apparatus for searching for an LTE network by a GSM-enabled terminal is provided in the embodiment of the present application, where the apparatus includes a first processing module 601 and a second processing module 602.

 The first processing module 601 is configured to retrieve, after searching for the GSM network, an LTE frequency point corresponding to the searched GSM network;

 The second processing module 602 is configured to search for the retrieved LTE frequency.

 The first processing module 601 has two search modes for the LTE network and the GSM network, one is to search for the LTE network and the GSM network synchronously, and the other is to perform the GSM network search first, and then the search is completed. For LTE network search, the following two search methods are introduced separately.

 Method 1: Synchronize search for LTE network and GSM network

 When searching for LTE network and GSM network synchronously, for LTE network search, LTE network search is performed according to the frequency of the last registered registration. For the GSM network search, the GSM network is searched according to the frequency point in the GSM frequency list.

 There are several cases in which the LTE network and the GSM network are searched synchronously.

 In the first case, when searching for the LTE network and the GSM network in synchronization, the search for the LTE network first performs the LTE network search according to the frequency of the last successful registration, and the last successful registration frequency registration and registration is successful. It is determined whether the LTE frequency point to be registered is stored in the LTE frequency list, and if it is stored in the LTE frequency list, the flow ends; if it is stored in the LTE frequency list, the LTE frequency list is updated and stored.

 In the second case, when searching for the LTE network and the GSM network synchronously, for the search of the LTE network, the LTE network search is performed according to the frequency of the latest registration success, and the LTE network is not searched, and the GSM network has already completed the search. The LTE frequency corresponding to the searched GSM network is retrieved, and the retrieved corresponding LTE frequency is searched. After the LTE frequency search for the GSM network is completed, to search for the registrable LTE frequency, the LTE network is searched according to the frequency point in the LTE frequency list.

 In the third case, when searching for the LTE network and the GSM network synchronously, the search for the LTE network first searches for the LTE network according to the frequency of the last successful registration, and does not search for the LTE network, and the GSM network does not complete the search. Then, the LTE network searches for the LTE network according to the frequency point in the LTE frequency list; before the LTE network performs the LTE network search according to the frequency point in the LTE frequency list, the GSM network search is completed, and the LTE network searches for the LTE currently being searched. After the frequency search is completed and the search is not successful, the LTE network search based on the frequency points in the LTE frequency list is temporarily stopped, and the corresponding LTE frequency search searched by the GSM network is performed. If the LTE network searches for the corresponding LTE, If the search is not successful at the frequency point, the LTE network search is continued according to the frequency point in the LTE frequency list.

In the fourth case, when searching for the LTE network and the GSM network synchronously, the search for the LTE network first searches for the LTE network according to the frequency of the last successful registration, and does not search for the LTE network, and the GSM network does not complete the search. Then, the LTE network searches for the LTE network according to the frequency point in the LTE frequency point list; according to the LTE network according to the LTE network When the LTE network search is successful in the frequency point list, the GSM network also completes the search. At this time, the terminal registers according to the searched LTE network frequency point, and searches whether the LTE frequency point is stored in the terminal's LTE frequency point list. If the LTE frequency list is already stored in the terminal, the process ends; if it is not stored in the LTE frequency list of the terminal, the LTE frequency list is updated, and the process is terminated after the update.

 Method 2: Search for the GSM network first, and search for the LTE network after the search is completed.

 Performing an LTE network search according to the frequency of the last successful registration, and searching for the GSM network according to the frequency point in the GSM frequency list; if the LTE network is not searched according to the frequency of the last successful registration, waiting for the completion of the GSM network search; After the GSM network search is completed, searching for the corresponding LTE frequency point searched by the GSM network, if the search is not successful in the corresponding LTE frequency point searched by the GSM network, the LTE network search is performed according to the frequency point in the LTE frequency point list. The specific search mode is basically the same as that of FIG. 3, and details are not described herein again.

 Preferably, the second processing module 602 is specifically configured to: during the search process of the LTE network, if the retrieved LTE frequency point search succeeds and is registered, whether the LTE frequency point is stored in the LTE frequency point list of the terminal, If it is stored in the LTE frequency list of the terminal, the process ends; if it is not stored in the LTE frequency list of the terminal, the LTE frequency list is updated, and the process is terminated after the update.

 The search method and device of the long term evolution network provided by the embodiment of the present application are configured to save the cell ID of the serving cell in the success list when the terminal searches for the LTE network, so as to be corresponding to the cell ID included in the terminal entry success list. When the terminal accesses the 2G or 3G network, the terminal automatically searches for the LTE network in the cell without waiting for the user to initiate searching for the LTE network, thereby improving the efficiency of the LTE network search.

 A specific implementation manner of a search method and apparatus for an LTE network according to an embodiment of the present application is described below with reference to the accompanying drawings.

 As shown in FIG. 7, the method for searching for an LTE network provided by the embodiment of the present application includes the following steps: S701: The terminal in the access 2G or 3G network determines whether the cell ID of the current service and the area exists in the success list. The LTE network is searched for in the cell corresponding to each cell ID included in the success list.

 S702. After determining that the cell ID of the current serving cell exists in the success list, the terminal searches for the LTE network in the current serving cell.

 In the above steps, the success list is obtained by the terminal adding the cell ID of the serving cell to the success list when searching for the LTE network, if the LTE network is successfully searched each time the terminal searches for the LTE network through the user setting. The terminal then determines whether the cell ID of the current serving cell is already included in the candidate list (or forbidden list), and if so, deletes the cell ID of the current serving cell from the candidate list (or the forbidden list).

 As the cell ID in the success list increases, the time for finding the cell ID will continue to increase. Therefore, a preferred method is to establish a location area identifier LA (Location Area) of the LA (Location Area) in the success list.

Identification, location area identifier) and cell ID correspondence; Correspondingly, as shown in FIG. 8, in S701, the specific steps when determining whether the success list includes the cell ID of the current serving cell include:

 57011, the terminal searches the success list for the cell ID corresponding to the LAI of the current LA;

 57012: The terminal determines whether there is a cell ID of the current serving cell in the found cell ID.

 This can narrow the scope of the search. When the success list includes more cell IDs, you can first find the LAI corresponding to the cell ID of the current serving cell, and then only determine whether there are current services in all cell IDs corresponding to the LAI. The cell ID of the cell improves the speed of the judgment, and further shortens the time for the terminal to search for the LTE network, thereby further improving the search efficiency of the LTE network.

 The successful list including the LAI is that after the terminal initiates the search for the LTE network command by the user setting, if the LTE network is successfully searched, the LAI of the LA and the cell ID of the serving cell are added to the success list when the LTE network is searched. The cell ID of the serving cell is obtained as the cell ID corresponding to the LAI of the LA. Then, the terminal also determines whether the cell ID of the current serving cell is already included in the candidate list (or the forbidden list), and if so, deletes the cell ID of the current serving cell from the candidate list (or the forbidden list).

 The cell ID of the serving cell as the cell ID corresponding to the LAI of the LA refers to the LA of the LA where the serving cell is located, that is, the LAI of the LA can find all the cell IDs corresponding to the LAI of the LA, and only needs to determine the serving cell. Whether the cell ID is in all the cell IDs found, and there is no such range, and the entire success list is certainly not. In this way, it is not necessary to find the cell ID of the serving cell in the entire success list, thereby quickly determining whether the cell ID of the serving cell exists in the success list.

 Further, as shown in FIG. 9, after determining that the cell ID of the current serving cell does not exist in the success list, the terminal further includes the following steps:

 S901: The terminal checks whether the cell ID of the current serving cell exists in the candidate list, where the cell corresponding to the cell ID included in the candidate list is a neighboring cell of the cell corresponding to the cell ID included in the success list.

 After determining that the cell ID of the current serving cell exists in the candidate list, the terminal determines whether the L AI of the current LA exists in the success list.

 S903. After determining that the LAI of the current LA exists in the success list, the terminal searches for the LTE network in the current serving cell.

 Increasing the candidate list is based on the fact that the cell added to the success list can search for the LTE network, and the possibility of searching for the LTE network in the cell adjacent thereto is also high, so for the cell ID in the candidate list, As long as its corresponding LAI is also in the success list, the terminal can automatically search for the LTE network. This can reasonably improve the terminal's automatic search for LTE probability, thereby further improving the efficiency of LTE network search.

If the cell ID of the current serving cell is in the candidate list, and the terminal searches for the LTE network in the current serving cell, the terminal deletes the cell ID of the current serving cell from the candidate list, and adds the cell ID of the current serving cell. Go to the success list and the cell ID that corresponds to the LAI of the current LA. Further, as shown in FIG. 10, after the terminal adds the cell ID of the current serving cell to the success list and is the cell ID corresponding to the LAI of the current LA, the following steps are further included:

 51010: The terminal determines that the cell ID of the neighboring cell of the current serving cell is not included in the success list, the candidate list, or the forbidden list.

 51011, the terminal adds the neighboring cell ID of the current serving cell to the candidate list.

 The foregoing prohibition list is that when the cell ID of the current serving cell is included in the candidate list and the LAI of the current LA is included in the success list, after the number of times the terminal fails to search for the LTE network in the current serving cell exceeds the threshold, the terminal will The cell ID of the serving cell is removed from the candidate list and added to the forbidden list.

 In a specific application, it may be determined that the number of times the terminal fails to search for the LTE network in the current serving cell exceeds the threshold.

 In the first manner, a number N of times for which the LTE network fails to be searched may be set for each cell ID when each cell ID is added to the candidate list. After each failure of searching for the LTE network, the number N is subtracted by 1 and the judgment is decreased. If the number of failed attempts to search for the LTE network after 1 is greater than 0, if not greater than 0, the cell ID of the current serving cell is deleted from the candidate list and added to the forbidden list.

 In the second manner, a number of times N for which the LTE network fails to be searched may be set for each cell ID when each cell ID is added to the candidate list, and the number of failed attempts to search for the LTE network when the cell ID is initially added to the candidate list is 0, after each search for the LTE network fails once, the number of failures of searching for the LTE network is increased by 1, and it is judged whether the number of failed attempts to search for the LTE network after adding 1 is less than N, and if not less than N, the cell of the current serving cell is The ID is removed from the alternate list and added to the forbidden list.

 The use of the forbidden list can overcome that when the terminal does not search for the LTE network at any position in the cell identified by some cell IDs included in the candidate list, the LTE can be searched in a neighboring cell of the cell. In the network, the cell ID of the neighboring cell of the cell is added to the success list, so that the cell ID of the cell of the terminal is added to the backup list, and when the terminal returns to the cell, the LTE network will not be searched. The cell ID of the cell is deleted from the backup list. If the terminal can search for the LTE network in more than one neighboring cell of the cell, the cell ID of the cell, that is, the cell ID of the cell that cannot search for the LTE network, is not obtained. , is continuously added to the backup list, and then deleted, so that the terminal repeatedly repeats the addition and deletion operations, thereby consuming the shortcomings of the terminal resources.

 In addition, using the forbidden list may also overcome when the terminal does not search for the LTE network in any location in the cell identified by some cell IDs included in the candidate list, since these cell IDs are present in the candidate list and The LAIs corresponding to the cell IDs are present in the success list, and the terminal continuously searches for the LTE network automatically in the cells identified by the cell IDs, so that the terminal power is consumed in a large amount.

 Therefore, the use of the forbidden list not only prevents the terminal resources from being wasted, but also prevents the terminal power from being unnecessarily lost.

FIG. 11 is a flowchart of a LTE network search method in a specific application according to an embodiment of the present application, including The following steps:

 SI 101, the terminal accessing the 2G or 3G network determines the LAI of the current LA and the cell ID of the current serving cell;

51102, the terminal determines whether the LAI of the current LA exists in the success list; if yes, executes S1103, and if not, executes S1105;

 51103, the terminal determines whether the cell ID of the current serving cell exists in the success list; if yes, execute S 1106, if not, execute S1104;

 51104, the terminal determines whether the cell ID of the current serving cell exists in the candidate list; if yes, execute S 1107, if not, execute S1105;

 51105, the terminal waits for the user to input an instruction for searching for the LTE network, and after receiving the instruction, searches for the LTE network in the current serving cell and determines to search for the LTE network, and then executes S1111;

 51106, the terminal searches for an LTE network in the current serving cell;

 51107, the terminal searches for the LTE network in the current serving cell and determines whether to search for the LTE network; if yes, execute S1110, if not, execute S1108;

 51108, the terminal confirms that the number of failures of searching for the LTE network in the current serving cell is greater than or equal to a threshold, and then executing S1109;

 51109, the terminal deletes the current service d, the area from the candidate list and adds it to the forbidden list;

 51110, the terminal deletes the cell ID of the current serving cell from the candidate list and adds it to the success list, and then executes S1115;

 51111, confirm that the LAI of the current LA has not been added to the success list, add the LAI of the current LA to the success list, and then execute S1112;

 51112, determining whether the cell ID of the current serving cell is included in the candidate list (or prohibit list); if yes, executing S1114, and if not, executing S1113;

 51113, the terminal directly adds the cell ID of the current serving cell to the success list and corresponds to the LAI of the current LA, and then executes S1115;

 51114, the terminal deletes the cell ID of the current serving cell from the candidate list (or the forbidden list), and then adds the cell ID of the current serving cell to the success list and corresponds to the LAI of the current LA, and then executes S1115;

 51115. Determine, that the cell ID of the neighboring cell of the current serving cell has not been added to the success list, the candidate list, or the forbidden list, and add the cell ID of the neighboring cell of the current serving cell to the candidate list.

 For the above search method, the embodiment of the present application further provides a search device for the LTE network corresponding to the method. As shown in FIG. 12, the device includes:

The determining module 121 is configured to determine whether a cell ID of the current serving cell where the terminal in the 2G or 3G network is located exists in the success list, where the terminal is in the cell corresponding to each cell ID included in the success list. Have searched for LTE networks; The processing module 122 is configured to determine that a cell ID of the current serving cell exists in the success list, and send an instruction to the terminal to search for the LTE network.

 The above list of successes is obtained as follows:

 The processing module 122 is further configured to: after receiving the instruction that the terminal successfully searches for the LTE network by using the user setting, and successfully searching for the LTE network, add the cell ID of the serving cell when searching for the LTE network to the success list. .

 Preferably, if the success list includes the location area identifier LAI of the location area LA and the cell ID corresponding to the LAI, the determining module 121 is further configured to search the success list for the cell ID corresponding to the LAI of the current LA, and determine the search. Whether there is a cell ID of the current serving cell in the obtained cell ID.

 The above successful list containing LAI is obtained as follows:

 The processing module 122 is further configured to: after receiving the instruction that the terminal initiates the search for the LTE network by using the user setting and successfully search for the LTE network, add the LAI of the LA and the cell ID of the serving cell when searching for the LTE network to In the success list, the cell ID of the serving cell is used as the cell ID corresponding to the LAI of the LA.

 Further, after determining that the cell ID of the current serving cell does not exist in the success list, the determining module 121 is further configured to check whether the cell ID of the current serving cell exists in the candidate list, where the cell ID included in the candidate list Corresponding cell is a neighboring cell of the cell corresponding to the cell ID included in the success list; and after determining that the cell ID of the current serving cell exists in the candidate list, determining whether the LAI of the current LA exists in the success list;

 The processing module 122 is further configured to: after determining that the LAI of the current LA exists in the success list, send an instruction to the terminal to search for the LTE network.

 Preferably, the processing module 122 is further configured to: after receiving the instruction that the terminal searches for the LTE network, delete the cell ID of the current serving cell from the candidate list, and add the cell ID of the current serving cell to the success list. It is the cell ID corresponding to the LAI of the current LA.

 Further, after the cell ID of the current serving cell is added to the success list and is the cell ID corresponding to the LAI of the current LA, the processing module 122 is further configured to determine that the cell ID of the neighbor cell of the current serving cell is not included in the success list. In the alternative list or the forbidden list, and add the neighbor cell ID of the current serving cell to the candidate list.

 Preferably, the processing module 122 is further configured to: after receiving the number of times that the terminal fails to search for the LTE network in the current serving cell, the cell ID of the current serving cell is deleted from the candidate list, and is added to the forbidden list. The terminal has never searched for an LTE network in a cell corresponding to each cell ID included in the forbidden list.

 Based on the same inventive concept as the method, the embodiment of the present application further provides a terminal for accessing a 2G or 3G network, and the terminal includes any of the foregoing devices.

Based on the same inventive concept as the method, the embodiment of the present application further provides a terminal for accessing a 2G or 3G network, where the terminal includes: a processor, the processor is configured to determine whether the cell ID of the current serving cell exists in the success list, where the cell corresponding to each cell ID included in the success list has searched for the LTE network; After the cell ID of the serving cell exists in the success list, the LTE network is searched for in the current serving cell.

 The terminal provided by the embodiment of the present application saves the cell ID of the serving cell in the success list when the terminal searches for the LTE network, so that the terminal enters the cell corresponding to the cell ID included in the success list and the terminal accesses the 2G. When the network is in the 3G network, the terminal automatically searches for the LTE network in the cell, instead of waiting for the user to initiate the search for the LTE network, thereby improving the efficiency of the LTE network search.

 Through the description of the above embodiments, those skilled in the art can clearly understand that the embodiments of the present application can be implemented by hardware, or can be implemented by means of software plus a necessary general hardware platform. Based on the understanding, the technical solution of the embodiment of the present application may be embodied in the form of a software product, which may be stored in a non-volatile storage medium shield (which may be a CD-ROM, a USB flash drive, a mobile hard disk, etc.). The tens of instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform the methods described in various embodiments of the present application.

 A person skilled in the art can understand that the drawings are only a schematic diagram of a preferred embodiment, and the modules or processes in the drawings are not necessarily required to implement the application.

 Those skilled in the art can understand that the modules in the apparatus in the embodiments may be distributed in the apparatus of the embodiment according to the description of the embodiments, or may be correspondingly changed in one or more apparatuses different from the embodiment. The modules of the above embodiments may be combined into one module, or may be further split into a plurality of sub-modules.

 It will be apparent to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit and scope of the application. Thus, it is intended that the present invention cover the modifications and variations of the present invention.

Claims

Rights request 1. A method for a GSM-supported terminal to search for an LTE network, characterized in that the method includes: after searching for a GSM network, the terminal retrieves the LTE frequency point corresponding to the searched GSM network; The terminal searches for the retrieved LTE frequency point. 2. The method of claim 1, wherein before the terminal searches for the GSM network, it further includes: the terminal searches for the LTE network and the GSM network simultaneously. 3. The method of claim 1 or 2, wherein the terminal searches for the LTE frequency point corresponding to the searched GSM network, including: After the terminal searches for the GSM network but does not search for the LTE network, it searches for the LTE frequency point corresponding to the searched GSM network. 4. The method of claim 3, further comprising: If the terminal first searches for the LTE network at the LTE frequency point corresponding to the GSM network, or searches for the LTE network and the GSM network simultaneously, it will register on the searched LTE network. 5. The method of claim 2, wherein the terminal's simultaneous search for the LTE network and the GSM network includes: The terminal searches for the LTE network based on the most recently successfully registered frequency point, and searches for the GSM network based on the frequency point in the GSM frequency point list; If the terminal does not search for the LTE network based on the most recently successfully registered frequency point, and the search for the GSM network is not completed, the terminal searches for the LTE network based on the frequency point in the LTE frequency point list. 6. The method according to claim 5, characterized in that, after the terminal searches for the GSM network and has not yet searched for the LTE network according to the LTE frequency point list, and before searching for the retrieved LTE frequency point, it also includes : The terminal stops searching for the LTE network based on the frequency points in the LTE frequency point list. 7. The method of claim 6, wherein after the terminal retrieves the LTE frequency point corresponding to the searched GSM network, it further includes: If the LTE frequency point corresponding to the GSM network is not retrieved or the retrieved LTE frequency point is searched and the LTE network is not searched, the terminal continues to search the LTE network according to the frequency point in the LTE frequency point list. 8. The method according to any one of claims 1, 2, 4-7, wherein the terminal searches for the LTE frequency point corresponding to the searched GSM network, including: The terminal determines the public land mobile communication network PLMN information of the searched GSM network, and retrieves the LTE frequency point corresponding to the searched GSM network based on the PLMN information. 9. A device that supports GSM terminals for searching LTE networks, characterized in that the device includes: The first processing module is used to retrieve the LTE frequency point corresponding to the searched GSM network after searching for the GSM network; The second processing module is used to search for the retrieved LTE frequency points. 10. The device according to claim 9, characterized in that the first processing module is used for: After searching for the GSM network but not searching for the LTE network, retrieve the LTE frequency corresponding to the searched GSM network; If the LTE network is searched first, or the LTE network and GSM network are searched simultaneously, register on the searched LTE network. 11. A long-term evolution LTE network search method, characterized by including: The terminal accessing the 2G or 3G network determines whether the cell ID of the current serving cell exists in the success list, where the terminal has searched for the LTE network in the cells corresponding to each cell ID included in the success list. ; After determining that the cell ID of the current serving cell exists in the success list, the terminal searches for the LTE network in the current serving cell. 12. The method of claim 11, wherein the success list includes the location area identifier LAI of the location area LA and the cell ID corresponding to the LAI; The terminal determines whether the cell ID of the current serving cell exists in the success list according to the following steps: The terminal searches the success list for the cell ID corresponding to the LAI of the current LA; The terminal determines whether the found cell ID contains the cell ID of the current serving cell. 13. The method of claim 11, wherein the success list is obtained in the following manner: each time the terminal initiates a search for the LTE network through user settings, if the LTE network is successfully searched, the terminal will search The cell ID of the serving cell when reaching the LTE network is added to the success list. 14. The method of claim 12, wherein the success list is obtained in the following manner: each time the terminal initiates a search for the LTE network through user settings, if the LTE network is successfully searched, the terminal will search When arriving at the LTE network, the LAI of the LA where the user is located and the cell ID of the serving cell are added to the success list, and the cell ID of the serving cell is used as the cell ID corresponding to the LAI of the LA where the user is located. 15. The method of claim 12, wherein after determining that the cell ID of the current serving cell does not exist in the success list, the terminal further includes: The terminal checks whether the cell ID of the current serving cell exists in the candidate list, wherein the cell corresponding to the cell ID contained in the candidate list is a neighboring cell of the cell corresponding to the cell ID contained in the success list; After determining that the cell ID of the current serving cell exists in the candidate list, the terminal determines the location of the current LA. Whether L AI exists in said success list; After determining that the LAI of the current LA exists in the success list, the terminal searches for the current serving cell. Search LTE network. 16. The method of claim 15, wherein after the terminal searches for the LTE network, it further includes: after the terminal searches for the LTE network, delete the cell ID of the current serving cell from the candidate list, And add the cell ID of the current serving cell to the success list and use it as the cell ID corresponding to the LAI of the current LA. 17. The method of claim 16, wherein after the terminal adds the cell ID of the current serving cell to the success list as the cell ID corresponding to the LAI of the current LA, it further includes: The terminal determines that the cell ID of the neighboring cell of the current serving cell is not included in the success list, the alternative list or the forbidden list, and adds the cell ID of the neighboring cell of the current serving cell to the alternative list. 18. The method of claim 17, wherein the method further includes: After the number of failed searches for the LTE network in the current serving cell exceeds a threshold, the terminal deletes the cell ID of the current serving cell from the alternative list and adds it to the prohibited list, where the terminal includes in the prohibited list The LTE network has never been searched in the cells corresponding to each cell ID. 19. A long-term evolution LTE network search device, characterized by including: Determination module, used to determine whether the cell ID of the current serving cell where the terminal accesses the 2G or 3G network is located exists in the success list, wherein the terminal corresponds to each cell ID included in the success list. Zhongjun has searched for LTE networks; A processing module configured to determine that the cell ID of the current serving cell exists in the success list, and send an instruction to search for the LTE network to the terminal. 20. The device according to claim 19, characterized in that, after determining that the cell ID of the current serving cell does not exist in the success list; The judgment module is also used to check whether the cell ID of the current serving cell exists in the alternative list, where the cell corresponding to the cell ID included in the alternative list is the cell corresponding to the cell ID included in the success list. neighboring cells; and after determining that the cell ID of the current serving cell exists in the candidate list, determine whether the LAI of the current LA exists in the success list; The processing module is also configured to send an instruction to search for the LTE network to the terminal after determining that the LAI of the current LA exists in the success list.