JP2013258623A - Mobile communication terminal and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile communication terminal of which the cell search time is shorter.SOLUTION: A mobile communication terminal 1 according to the invention comprises: a cell search unit 12 which acquires PLMN information from notification information received from a base station; and a cell search control unit 13 which instructs the cell search unit 12 to acquire the PLMN information when the mobile communication terminal is out of the service area, and determines an available base station on the basis of the PLMN information acquired by the cell search unit 12. When the cell search unit 12 has acquired a preset prescribed number of pieces of the PLMN information, it outputs the acquired PLMN information to the cell search control unit 13. On the basis of the PLMN information output by the cell search unit 12, if the cell search control unit 13 found an available base station, it starts restoration-to-service-area processing with the base station.

Description

  The present invention relates to a mobile communication terminal and a control method thereof, and more particularly to a mobile communication terminal connected to a public mobile network and a control method thereof.

  Unlike a fixed communication terminal, a mobile communication terminal sometimes falls into a situation where it cannot enjoy communication services due to radio wave conditions or the like. In such a case, the mobile communication terminal needs to connect to the network again.

  Patent Document 1 describes a roaming control method in a multimode terminal. The terminal described in Patent Document 1 is a multimode terminal that can be connected to a first wireless communication network and a second wireless communication network. When it is determined that the terminal is roaming to the first wireless communication network, the terminal stops the connection operation to the second communication network.

JP2011-259435A

  However, in order for the user to use the communication service more comfortably, it is necessary to return to the connection state to the network, that is, the in-zone state in a shorter time. In the technique described in Patent Document 1, the connection to the second communication network is stopped when roaming to the first wireless communication network, so the connection time to the first communication network is shortened. I can't do it.

  The operation when a general mobile communication terminal connects to a cell, that is, performs Camp On will be further described. FIG. 3 is a diagram illustrating an operation when the mobile communication terminal 101 performs Camp On to a cell. The mobile communication terminal 101 includes a cell search control unit 102 and a cell search unit 103 controlled by the cell search control unit 102.

  Here, the cells that the mobile communication terminal can communicate with are cell a, cell b, and cell c, and the cell to which the mobile communication terminal 101 can transition to the in-range state (herein referred to as “Camp On capable cell”). ) Is a cell b.

  When the mobile communication terminal 101 detects out-of-service 105 (step S201), the cell search control unit 102 acquires, from the cell search unit 103, PLMN (Public Land Mobile Network) information of cells existing around the mobile communication terminal 101. Is requested (step S202).

  Receiving the PLMN information income request, the cell search unit 103 detects cells in the vicinity of the mobile communication terminal 101, and acquires broadcast information including the PLMN information of the cells a to c in the order of detection (steps S203 to S205). . Here, the detection order is cell a, cell b, and cell c.

  After acquiring the PLMN information of all cells (step S206), the cell search unit 103 notifies the cell search control unit 102 that the acquisition of the PLMN information is completed, and outputs the PLMN information to the cell search control unit 102. (Step S207).

  The cell search control unit 102 determines from the received PLMN information whether or not Camp On is possible (step S208), and starts the area return processing for the cell corresponding to the PLMN information (step S209).

  When a general mobile communication terminal performs Camp On on a cell, whether or not the cell can be Camp On using the PLMN information after acquiring PLMN information of all cells that can be detected by the cell search unit. judge. That is, cell determination is not performed until PLMN information of all cells is acquired. Therefore, there has been a problem that the cell search takes time.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a mobile communication terminal having a shorter return time to the in-zone state.

  A mobile communication terminal according to the present invention includes a cell search unit that acquires PLMN information from broadcast information received from a base station, and instructs the cell search unit to acquire PLMN information when out of service, and a cell search unit A cell search control unit that determines a base station that can be used based on the PLMN information acquired in step 1. The cell search unit acquires the predetermined number of preset PLMN information and acquires the cell search control unit. The PLMN information is output, and when the cell search control unit finds an available base station based on the PLMN information output from the cell search unit, the cell search control unit starts the area return processing for the base station. is there.

  The mobile communication terminal control method according to the present invention acquires PLMN information when it is out of service area, and is acquired when a predetermined number of preset PLMN information is acquired from broadcast information received from a base station. Based on the PLMN information, an available base station is determined, and when there is an available base station, the area return processing with the base station is started.

  According to the present invention, a mobile communication terminal with a shorter cell search time can be provided.

1 is a diagram illustrating a mobile communication terminal according to a first embodiment. FIG. 3 is a diagram illustrating an operation of the mobile communication terminal according to the first exemplary embodiment. It is a figure which shows operation | movement of a general communication terminal.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a mobile communication terminal 1 according to the present embodiment. The mobile communication terminal 1 communicates with any one or more of the base stations 31 to 33.

  The mobile communication terminal 1 includes an antenna 10, a radio reception unit 11, a cell search unit 12, a cell search control unit 13, and a PLMN information storage unit 14 as a storage unit. The mobile communication terminal 1 is specifically a mobile phone terminal, a tablet terminal or the like. The mobile communication terminal 1 has a display as an output unit, a processing unit that performs internal arithmetic processing, and the like, but description thereof is omitted here.

  The base stations 31 to 33 communicate with the mobile communication terminal 1 and transmit broadcast information including a PLMN number. The antenna 10 transmits and receives radio waves to and from the base stations 31 to 33. The wireless receiving unit 11 demodulates the radio wave received by the antenna 10 and converts the signal output from the mobile communication terminal 1 into a radio wave.

  The PLMN information storage unit 14 stores a PLMN number of a base station with which the mobile communication terminal 1 can communicate.

  The cell search unit 12 scans the signals output from the base stations 31 to 33 demodulated by the radio reception unit 11. The cell search unit 12 acquires broadcast information including area information of the base station. The broadcast information includes the PLMN number of each base station. The cell search unit 12 outputs the acquired PLMN number to the cell search control unit 13 every time a predetermined number of preset PLMN numbers are acquired. Typically, every time one PLMN number is acquired, it is output to the cell search control unit 13.

  Here, the PLMN number is a mobile country code (MCC), that is, a country code, and a mobile country network code (MNC), that is, an operator number in the 3GPP (Third Generation Partnership Project) standard. And the number. By acquiring the PLMN number, the operator of the base station that has output the PLMN number can be determined, and it can be determined whether or not the base station can be used.

  The cell search control unit 13 controls the cell search unit 12 to cause the cell search unit 12 to acquire a PLMN number. Each time the cell search control unit 13 receives a PLMN number from the cell search unit 12, the cell search control unit 13 compares the PLMN number stored in the PLMN information storage unit 14 with the PLMN number acquired by the cell search unit 12.

  When the PLMN number acquired by the cell search unit 12 matches the PLMN number stored in the PLMN information storage unit 14, it is determined that the base station corresponding to the acquired PLMN number is a base station suitable for communication. . Then, the mobile communication terminal 1 establishes communication with the base station determined to be appropriate.

  Next, the operation of the mobile communication terminal 1 according to this embodiment will be described. FIG. 2 is a diagram illustrating an operation of the mobile communication terminal 1 according to the present embodiment. Here, it is assumed that the cell search unit 12 acquires the PLMN numbers in the order of the base stations 31 to 32 and 33, and the base station 32 is a base station that can be used by the mobile communication terminal 1. The cell search unit 12 will be described as outputting to the cell search control unit 13 every time one PLMN number is acquired. In addition, the cell search control unit 13 stops the PLMN information acquisition process of the cell search unit 12 when an available base station is found based on the PLMN number.

  First, the mobile communication terminal 1 detects out of range (step S101). When cell search control unit 13 detects out-of-service, it outputs a broadcast information acquisition request to cell search unit 12 (step S102).

  When the broadcast information acquisition request is output, the cell search unit 12 starts acquiring broadcast information. Here, it demonstrates as what acquires the alerting | reporting information of the base station 31 first. The cell search unit 12 scans the signal demodulated by the radio reception unit 11, acquires broadcast information including the PLMN number of the base station 31, and outputs the broadcast information to the cell search control unit 13 (step S103). Here, the cell search unit 12 continues the PLMN number acquisition process even after outputting the PLMN number to the cell search control unit 13.

  The cell search control unit 13 receives the PLMN number from the cell search unit 12 and compares it with the PLMN number stored in the PLMN information storage unit 14. Then, it is determined whether or not the base station corresponding to the acquired PLMN number is a base station that can be used by the mobile communication terminal 1 (step S104).

  When the cell search unit 12 outputs the PLMN number of the base station 31 to the cell search control unit 13, the cell search unit 12 starts acquiring broadcast information of another base station. Here, the broadcast information of the base station 32 is acquired. The cell search unit 12 scans the signal demodulated by the radio reception unit 11 and acquires broadcast information including the PLMN number of the base station 32 (step S105).

  The cell search unit 12 outputs the acquired PLMN number of the base station 32 to the cell search control unit 13 (step S106). The cell search control unit 13 receives the PLMN number from the cell search unit and compares it with the PLMN number stored in the PLMN information storage unit 14. Then, it is determined whether or not the base station corresponding to the acquired PLMN number is a base station that can be used by the mobile communication terminal 1 (step S107). Since the base station 32 is a base station that can be used by the mobile communication terminal 1, the PLMN number acquired by the cell search unit 12 matches the PLMN number stored in the PLMN information storage unit 14.

  The cell search control unit 13 determines whether the PLMN number acquired by the cell search unit 12 matches the PLMN number stored in the PLMN information storage unit 14 (step S108). Then, the cell search control unit 13 requests the cell search unit 12 to stop acquiring the PLMN number (step S109).

  When receiving the PLMN number acquisition stop request from the cell search control unit 13, the cell search unit 12 stops acquiring the PLMN number (step S110). Then, when the PLMN acquisition process stop is completed, the cell search unit 12 outputs an acquisition stop completion notification to the cell search control unit 13 (step S111).

  Upon receiving the acquisition stop completion notification from the cell search unit 12, the cell search control unit 13 communicates with the base station 32 and starts the area return processing (step S112).

  In the mobile communication terminal 1 according to the present embodiment, when the mobile communication terminal 1 in the out-of-service state is in an environment that can return to the service area, cell search control is performed each time the cell search unit 12 acquires broadcast information of one cell. The unit 13 determines the base station corresponding to the broadcast information from the PLMN information included in the broadcast information. When the cell search control unit 13 determines that the broadcast information necessary for returning to the in-zone state has been acquired, the broadcast information acquisition process of the cell search unit 12 is stopped.

  Therefore, according to this embodiment, communication between the mobile communication terminal and the base station is established compared to the conventional technique in which the available base stations are determined after waiting for acquisition of information of all base stations. It is possible to shorten the time to do.

  In the present embodiment, even after it is determined that the base station corresponding to the PLMN information acquired by the cell search unit 12 is available, the cell search control unit 13 causes the cell search unit 12 to send the PLMN information. Acquisition may be continued. Then, when a base station with better communication quality than the base station determined to be usable first is found, the connection destination may be changed to a good base station. This makes it possible to find a base station with higher communication quality while shortening the cell search time. Also, the cell search method according to the present embodiment can be used, for example, when the mobile communication terminal is turned on from power-off or during User Reselection.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Mobile communication terminal 10 Antenna 11 Radio | wireless receiving part 12 Cell search part 13 Cell search control part 14 PLMN information storage part 31 Base station 32 Base station 33 Base station 101 Mobile communication terminal 102 Cell search control part 103 Cell search part

Claims (7)

A cell search unit for obtaining PLMN information from broadcast information received from a base station;
A cell search control unit for instructing the cell search unit to acquire PLMN information when it is out of service area, and determining an available base station based on the PLMN information acquired by the cell search unit,
When the cell search unit acquires a predetermined number of preset PLMN information, it outputs the acquired PLMN information to the cell search control unit,
When the cell search control unit finds an available base station based on the PLMN information output from the cell search unit, the cell search control unit starts a range return process for the base station.   The mobile communication terminal according to claim 1, wherein the cell search unit continues to acquire the PLMN information without interruption even after outputting the PLMN information.   3. The cell search control unit according to claim 1, wherein when the cell search control unit finds an available base station based on the PLMN information acquired by the cell search unit, the cell search control unit causes the cell search unit to stop acquiring PLMN information. Mobile communication terminal.   3. The mobile communication terminal according to claim 1, wherein the cell search control unit causes the cell search unit to continue acquiring PLMN information until the cell search unit acquires all obtainable PLMN information.   The mobile communication terminal according to claim 4, wherein when a base station with better call quality than a base station that has been determined to be usable first is found, the connection destination is changed to a good base station.   The mobile communication terminal according to claim 1, wherein the predetermined number of PLMN information acquired by the cell search unit is one. When you are out of service area, get PLMN information,
When a predetermined number of preset PLMN information is acquired from the broadcast information received from the base station,
Determine available base stations based on the acquired PLMN information,
A method for controlling a communication terminal, in which, when there is a base station that can be used, starts a return processing within range with the base station.

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