JP2009302645A - Mobile communication terminal, and cell search method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal and a cell search method which can reduce a period of time needed for cell search and suppressing power consumption even when being out of range of communication. <P>SOLUTION: The mobile communication terminal includes: a radio clock part for receiving standard frequency radio time announcement radio wave transmitted from standard frequency time announcement stations different from country to country or from region to region; a location detection part to output a location of its own terminal specified on the basis of the standard frequency time announcement radio wave received by the radio clock part as location information; an object information storage part for storing cell search object information used by a plurality of mobile object communication systems respectively in association with the location information; a search object selection part for selecting cell search object information to be used in searching for cells to detect a radio base station of a mobile object communication system from the object information storage part; and a radio communication part for searching for cells by using cell search object information selected by the search object selection part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile communication terminal and a cell search method, and more particularly to a mobile communication terminal and a cell search method for performing communication using a plurality of mobile communication systems.

  When a mobile communication terminal, for example, a mobile phone or a portable information terminal establishes communication in a mobile communication system, it first searches for a communicable radio base station (cell). This operation of the mobile communication terminal is called cell search. There are cases where a “cell” indicates only a radio base station, and a case where it indicates a space area that can be connected (communication) with the radio base station and the radio base station. Sometimes, it is simply referred to as a “cell”. Hereinafter, a state in which the mobile communication terminal can communicate with the radio base station is referred to as “located”, and a state in which communication with any of the radio base stations cannot be performed is referred to as “out of range”.

  A mobile communication terminal is connected to a plurality of mobile communication systems such as W-CDMA (Wideband Code Division Multiple Access), GSM (Global System for Mobile communications), and wireless LAN (Local Area). Network (wireless LAN), WiMAX (Worldwide Interoperability for Microwave Access; WiMAX), etc. It is necessary to perform a search. As the number of mobile communication systems supported by mobile communication terminals increases, the number of communication methods and frequency ranges subject to cell search increase, the time required for cell search increases, and the power consumption of mobile communication terminals also increases. .

On the other hand, a mobile communication terminal that performs communication corresponding to a mobile communication system provided by a plurality of business operators, etc., corresponds to any one of the plurality of mobile communication systems. There is a technique for changing a time interval for performing a cell search based on information obtained by receiving a signal transmitted from a radio base station (Patent Document 1). This suppresses an increase in power consumption due to cell search in the mobile communication terminal. Here, the information obtained by receiving a signal is information such as the frequency of cell transition and the received signal strength.
In addition, in a mobile communication terminal that performs communication using a plurality of mobile communication systems, an MCC (Mobile Country Code) obtained from a received signal corresponding to any one of the plurality of mobile communication systems. There is a technique for limiting the frequency range of cell search of other mobile communication systems based on (country code) (Patent Document 2). Thereby, in the mobile communication terminal, an increase in time and power consumption required for cell search is suppressed.
JP 2004-356684 A JP 2004-23391 A

However, in the technique disclosed in Patent Document 1, it is necessary to receive any signal among a plurality of mobile communication systems, that is, to be located in any mobile communication system. In addition, there is a problem that the above method cannot be used immediately after power is supplied to the mobile communication terminal.
In the technique disclosed in Patent Document 2, the mobile communication system having a function of notifying the country code is used to limit the cell search frequency range of other mobile communication systems based on signals received within a certain period in the past. Do. Therefore, there is a problem that it is not possible to limit the frequency range of the cell search when the mobile communication system cannot communicate within the past certain period and the country code is not obtained.

  The present invention has been made to solve the above-mentioned problem, and its object is to reduce the time required for cell search and reduce power consumption even when the mobile communication terminal is out of service. It is to provide a terminal and a cell search method.

(1) In order to solve the above problem, the present invention is a mobile communication terminal that performs wireless communication in a plurality of mobile communication systems having different communication methods or frequency ranges, and different standard frequency reports for each country or region. A radio wave clock unit that receives a standard frequency time signal transmitted from a time station, and a position detection unit that outputs, as position information, the position of the terminal identified based on the standard frequency time signal received by the radio time signal unit Cell search target information used for each of the plurality of mobile communication systems is stored in association with the position information, and based on the position information input from the position detection unit Search target selection for selecting the cell search target information to be used when performing a cell search for detecting a radio base station of the mobile communication system from the target information storage unit When using the cell search target information the search target selecting unit selects a wireless communication unit for performing the cell search, a mobile communication terminal comprising: a.
In this mobile communication terminal, by receiving the standard frequency time signal, the position detection unit specifies the position of the terminal and outputs the position information as position information. Further, in the mobile communication terminal, based on the position information, the search target selection unit reads the search target information of the mobile communication system in which the service is performed, and selects the cell search target. Thereby, the mobile communication terminal can limit the cell search target, and can suppress the time and power consumption required for the cell search.
In addition, this mobile communication terminal includes a target information storage unit that stores the communication method used by the mobile communication system and the cell search target information in the frequency range in association with each location information, so that the mobile communication terminal is provided for each country or region. It becomes possible to set cell search target information used for cell search in detail. It is also possible to set only two cell search target information for a specific country or region, other countries or regions.

(2) Moreover, the present invention provides the mobile communication terminal according to the above-described invention, wherein the search target selection unit further includes, for each predetermined time interval, all the plurality of movements supported by the radio communication unit. The communication method or the frequency range used in the body communication system is selected and output to the wireless communication unit as the cell search target information.
This mobile communication terminal is configured to perform cell search using a communication method and frequency range used in all mobile communication systems supported by the wireless communication unit at regular time intervals. As a result, a radio base station having a communication method and frequency range not associated with the specified location information, for example, a communication method and frequency range newly provided in the country or region where the mobile communication terminal exists is detected. It becomes possible.

(3) Further, in the mobile communication terminal according to the above-described invention, the present invention provides the cell search target used when the radio communication unit detects the radio base station by the cell search. Information is output to the search target selection unit, and the search target selection unit stores the cell search target information input from the wireless communication unit in association with the position information input from the position detection unit. If not, the position information and the inputted cell search target information are associated with each other and written and stored in the target information storage unit.
This mobile communication terminal is configured such that the search target selection unit adds search target information stored in the target information storage unit. Accordingly, cell search target information used in a mobile communication system newly provided by a business operator or the like in the country or region can be added and stored in the target information storage unit. As a result, it is possible to reduce the time and power consumption required for subsequent cell searches.

(4) Further, according to the present invention, in the mobile communication terminal according to the invention described above, the radio clock unit receives standard frequency time signals transmitted from a specific number of standard frequency time signal stations. It is characterized by.
Cell search target information corresponding to location information stored in the target information storage unit is reduced by limiting the standard frequency time signal received by the radio clock unit and reducing the number of countries or regions specified by the location detection unit. . As a result, the processing performed by the radio clock unit and the position detection unit and the storage area required by the target information storage unit can be reduced, and the size and cost of the mobile communication terminal can be reduced.

(5) Further, the present invention is the mobile communication terminal according to the invention described above, wherein the cell search target information is information including information on the communication scheme or the frequency range.

(6) Further, the present invention performs wireless communication in a plurality of mobile communication systems having different communication methods or frequency ranges, and cell search target information used for each of the plurality of mobile communication systems indicates the position of the terminal itself. A cell search method in a mobile communication terminal including a target information storage unit stored in association with position information to be indicated, wherein a radio clock unit is transmitted from a standard frequency time signal station that is different for each country or region A process of receiving a frequency reporting radio wave, a process of outputting a position of the terminal identified by the position detection unit based on the standard frequency reporting radio wave received by the radio clock unit as position information, and a search target selection unit The cell search target information used when performing a cell search for detecting a radio base station based on the position information input from the position detection unit is the target information. A cell search method comprising: selecting from a storage unit; and a step of performing a cell search using a cell search target information selected by the search target selection unit by a radio communication unit. .
In this cell search method, by receiving a standard frequency time signal, the position detection unit identifies the position of the terminal itself and stores it as position information. Further, based on the position information, the search target selection unit selects the communication method and frequency range of the mobile communication system in which the service is performed. By using only the selected communication method and frequency range for the cell search, it is possible to suppress the time and power consumption required for the cell search even in an out-of-service state where the mobile communication terminal cannot communicate with the radio base station. Become.

  According to the present invention, when the mobile communication terminal receives the standard frequency time signal when the mobile communication terminal is out of service, the position detection unit identifies the position of the terminal and outputs it as position information. Furthermore, the mobile communication terminal reads the search target information of the mobile communication system in which the service is performed based on the location information, and determines the communication method and frequency range to be subject to cell search. You can choose. As a result, the mobile communication terminal can reduce the time and power consumption required for the cell search.

  Hereinafter, a mobile communication terminal and a cell search method according to an embodiment of the present invention will be described with reference to the drawings. The mobile communication terminal is a device that performs communication such as a mobile phone or a portable information terminal. Cell search refers to detecting a radio base station to which a mobile communication terminal is connected in order to receive a service for transmitting and receiving information.

(First embodiment)
FIG. 1 is a schematic block diagram showing the internal configuration of the mobile communication terminal 1 according to the first embodiment. The mobile communication terminal 1 includes a radio clock unit 11, a position detection unit 12, a target information storage unit 13, a search target selection unit 14, a wireless communication unit 15, and an antenna 17.

  The radio clock unit 11 has a function of receiving a plurality of standard frequency signal radio waves (hereinafter referred to as “standard radio waves”) transmitted from a standard frequency signal radio station as a national standard or an international standard. Further, the radio clock unit 11 outputs information included in the received standard radio wave, for example, date and time information, time information, a call code of the transmitting station, and information indicating the frequency of the received standard radio wave to the position detection unit 12. The standard radio wave includes date and time information, time information, a call code, and the like in the time format of each region.

  The position detection unit 12 specifies the position where the own terminal, that is, the mobile communication terminal 1 exists, based on the information included in the standard radio wave input from the radio clock unit 11 and the frequency of the received standard radio wave. Among the information included in the standard radio wave, for example, the time format and the calling code are different for each standard frequency time signal transmission station, so that the position detection unit 12 performs mobile communication based on the information included in the standard radio wave. The position where the terminal 1 exists can be specified. The position that can be specified by receiving the standard radio wave is a country or a region. Further, the position detection unit 12 outputs position information indicating the position of the identified own terminal to the search target selection unit 14.

  The target information storage unit 13 stores cell search target information in advance in association with each of a plurality of pieces of position information, that is, information on a mobile communication system provided in each country or region is recorded. . Here, the cell search target information is information including information indicating a communication method used in a mobile communication system and a frequency range used in wireless communication. Here, the communication method is a communication method defined by a wireless communication standard, such as a W-CDMA method, a GSM method, or a WiMAX method.

  The search target selection unit 14 reads cell search target information corresponding to the position information input from the position detection unit 12 from the target information storage unit 13 and outputs the cell search target information to the wireless communication unit 15. In addition, the search target selection unit 14 stores position information when the position information input from the position detection unit 12 and the communication method and frequency range input from the wireless communication unit 15 are not stored in association with each other. The communication method and the frequency range used in the mobile communication system are written and stored in the target information storage unit 13 in association with each other. Details of this point will be described later.

  The wireless communication unit 15 has a function of performing communication with a plurality of mobile communication systems. For example, the wireless communication unit 15 corresponds to a communication method such as a W-CDMA method or a GSM method, and has a generally known function of transmitting and receiving information via the antenna 17 in a plurality of frequency ranges. In addition, the wireless communication unit 15 uses the cell search target information input from the search target selection unit 14 to perform a cell search for detecting a communicable radio base station via the antenna 17. In addition, the radio communication unit 15 outputs to the search target selection unit 14 whether or not the radio base station has been detected, and determines the communication method and frequency range used for transmission / reception with the radio base station obtained as a result of the cell search. The data is output to the search target selection unit 14.

  FIG. 2 is a flowchart showing a cell search operation performed by the mobile communication terminal 1 according to the first embodiment. The cell search operation shown in the figure is performed in an out-of-service state where the mobile communication terminal 1 cannot receive radio waves from any radio base station immediately after power is supplied, or cannot communicate with the radio base station. This is the operation to be performed. Hereinafter, a state immediately after starting to supply power to the mobile communication terminal 1 will be described.

  First, in the mobile communication terminal 1, when power is started to be supplied, the search target selection unit 14 determines all the movements to which the wireless communication unit 15 corresponds in order to determine whether or not the own terminal is in the service area. The communication method and frequency range used in the body communication system are selected as cell search targets, and the selected communication method and frequency range are output to the radio communication unit 15 as cell search target information (step S11).

  When the cell search target information is input from the search target selection unit 14, the wireless communication unit 15 performs a cell search for the communication method and frequency range included in the input cell search target information, and is the in-service area state? It is determined whether or not (step S12).

When the wireless communication unit 15 detects a communicable wireless base station, that is, in the case of a located state (step S12: Y), the wireless communication unit 15 includes information indicating that a communicable wireless base station has been detected, The communication method and frequency range used when detecting the radio base station are output to the search target selection unit 14. When the search target selection unit 14 determines that the current position information is not stored in the target information storage unit 13 in association with the communication method and frequency range input from the wireless communication unit 15, the search target selection unit 14 Writes and stores the communication method and the frequency range in the target information storage unit 13 as cell search target information.
The mobile communication terminal 1 ends the cell search (end).

  If the radio communication unit 15 cannot detect a communicable radio base station, that is, if it is out of service area (step S12: N), the radio communication unit 15 searches for information indicating that the radio base station could not be detected. The data is output to the selection unit 14. The search target selection unit 14 outputs information instructing the radio wave clock unit 11 to receive the standard radio wave via the position detection unit 12 (step S13).

  When the radio clock unit 11 receives instruction information from the search target selection unit 14 and starts receiving the standard radio wave and receives the standard radio wave (step S13: Y), the radio wave clock unit 11 is included in the standard radio wave received by the position detection unit 12. Information and information indicating the frequency of the standard radio wave are output to the position detector 12. The position detection unit 12 determines the position where the mobile communication terminal 1 is present, for example, the country or the region, based on the information included in the standard radio wave input from the radio clock unit 11 and the information indicating the frequency of the standard radio wave. Identify as information. Further, the position detection unit 12 outputs the specified position information to the search target selection unit 14 (step S14).

  The search target selection unit 14 reads out and selects cell search target information corresponding to the position information input from the position detection unit 12 from the target information storage unit 13. Further, the search target selection unit 14 outputs the selected cell search target information to the radio communication unit 15 (step S15).

  On the other hand, when the radio clock unit 11 receives the instruction information from the search target selection unit 14 and starts to receive the standard radio wave and cannot receive the standard radio wave (step S13: N), it indicates that the standard radio wave has not been received. Information is output to the position detector 12. When the position detection unit 12 receives information indicating that the standard radio wave input from the radio wave clock unit 11 cannot be received, the position detection unit 12 outputs information indicating that the position information cannot be obtained to the search target selection unit 14. To do. When information indicating that position information cannot be obtained from the position detection unit 12 is input to the search target selection unit 14, the search target selection unit 14 selects communication methods and frequency ranges used in all mobile communication systems supported by the wireless communication unit 15. The selected communication method and frequency range are output to the wireless communication unit 15 as cell search target information (step S16). Here, the communication method and frequency range selected by the search target selection unit 14 are the same as the communication method and frequency range selected by the search target selection unit 14 in step S11.

When the cell search target information is input from the search target selection unit 14, the wireless communication unit 15 performs a cell search for the communication method and frequency range included in the input cell search target information (step S17).
If all frequencies are selected in step S16, searching for all frequencies in step S17 increases power consumption. Therefore, the communication method and frequency of the mobile communication system that has been in the area until just before is searched. A cell search may be performed only on the range.

  When the wireless communication unit 15 detects a wireless base station that can communicate by cell search, that is, in the presence state (step S18: Y), the wireless communication unit 15 determines the communication method and frequency corresponding to the detected wireless base station. The range is output to the search target selection unit 14. When the search target selection unit 14 determines that the communication method and frequency range input from the wireless communication unit 15 and the current position information are not stored in the target information storage unit 13, the search target selection unit 14 The information is input in association with the input communication method and frequency range, written as cell search target information, and stored in the target information storage unit 13 (step S19).

  The mobile communication terminal 1 enters a service area state and ends the cell search operation (end).

  If the radio communication unit 15 cannot detect a radio base station that can communicate by cell search, that is, if it is out of range (step S18: N), the mobile communication terminal 1 is in an out of range state. Repeat until you reach the service area. That is, the radio communication unit 15 performs a cell search for the communication method and frequency range selected as the cell search target information in steps S15 and S16 (step S17), and whether or not a communicable radio base station has been detected. That is, the determination of whether or not being in the service area (step S18) is repeated until the service area is reached.

  With the above operation, the mobile communication terminal 1 performs a cell search. As described above, in the mobile communication terminal 1, the search target selection unit 14 outputs cell search target information to be subjected to cell search to the radio communication unit 15, and the radio communication unit 15 performs cell search based on the cell search target information. Perform a search. As a result, it is possible to limit the communication method and frequency range used in the mobile communication system targeted for cell search, and it is possible to reduce the time required for cell search and the power consumption by cell search.

  Further, by adding the cell search target information stored in the target information storage unit 13, it is possible to select an appropriate communication method and frequency range when performing subsequent cell searches. For example, even when a frequency range is added to a communication system in a certain country or region, or when a service using a communication system that has not been provided is started, the time required for cell search is reduced. It becomes possible.

In addition, although the state immediately after starting to supply power to the mobile communication terminal 1 has been described, the mobile communication terminal 1 has any out-of-service state in all mobile communication systems from the existing state in any mobile communication system. The same cell search operation is performed even when
Further, in step S11, the communication of the mobile communication system that has been in the area immediately before without performing a cell search for the communication method and frequency range used in all the mobile communication systems supported by the wireless communication unit 15 is performed. You may perform a cell search only with respect to a system and a frequency range. This is because when the mobile communication terminal 1 is moving, even if the mobile communication terminal 1 is once out of service, it may be in the service area again. As described above, by limiting the communication method and frequency range to be subjected to the cell search, it is possible to suppress the time and power consumption required for the cell search.

  Further, in the case of the out-of-service state at step S18, the operation after step S17 may be performed after a certain period of time without immediately repeating the operation after step S17. At that time, the mobile communication terminal 1 includes a timer, and after detecting the lapse of a certain time, the radio communication unit 15 performs a cell search again. As a result, the frequency of cell search can be suppressed, and power consumption due to cell search can be suppressed.

(Second Embodiment)
FIG. 3 is a schematic block diagram showing the internal configuration of the mobile communication terminal 1A according to the second embodiment. The mobile communication terminal 1A includes a radio wave clock unit 11, a position detection unit 12, a target information storage unit 13, a search target selection unit 14A, a wireless communication unit 15, a timer unit 16, and an antenna 17.
Since the mobile communication terminal 1A has the same configuration as that of the mobile communication terminal 1 of the first embodiment except for the search target selection unit 14A and the timer unit 16, the same reference numerals 11 to 13, 15, and 17 are assigned thereto. The description will be omitted, and the search target selection unit 14A and the timer unit 16 having different configurations will be described below.

14 A of search object selection parts read and select the cell search object information corresponding to the positional information input from the position detection part 12 from the object information storage part 13, and output the selected cell search object information to the radio | wireless communication part 15. . In addition, the search target selection unit 14 </ b> A includes a communication method used in the mobile communication system to which the wireless communication unit 15 corresponds every time information indicating that the timer has expired is input from the timer unit 16. All the frequency ranges are selected and output to the wireless communication unit 15 as cell search target information. Thereby, a cell search is performed for every fixed time interval using all the communication systems and frequency ranges used with the mobile communication system with which the radio | wireless communication part 15 respond | corresponds.
When information indicating that the wireless communication unit 15 is out of service is input from the wireless communication unit 15 via the search target selection unit 14A, the timer unit 16 starts counting and expires every time a predetermined time elapses. Is output to the search target selection unit 14A.

  FIG. 4 is a flowchart showing a cell search operation of the mobile communication terminal 1A according to the second embodiment. The cell search operation shown in the figure is in a state in which the mobile communication terminal 1A is not able to receive radio waves from any radio base station immediately after power is supplied, and cannot communicate with the radio base station (out-of-service state) This is the operation to be performed. Hereinafter, the state immediately after starting to supply power to the mobile communication terminal 1A will be described.

  First, in the mobile communication terminal 1A, when power is started to be supplied, the search target selection unit 14A determines all the movements supported by the wireless communication unit 15 in order to determine whether or not the own terminal is in the service area. The communication method and frequency range of the body communication system are selected as cell search targets and output to the wireless communication unit 15 (step S11A).

  When the cell search target information is input from the search target selection unit 14A, the wireless communication unit 15 performs a cell search based on the input cell search target information and determines whether or not the mobile terminal is in a service area state ( Step S12A).

  When the wireless communication unit 15 detects a communicable wireless base station, that is, in the presence state (step S12A: Y), the operation of step S21A described later is performed.

  On the other hand, if the wireless communication unit 15 cannot detect a wireless base station that can communicate with all the communication systems and frequency ranges of the mobile communication system, that is, in the out-of-service state (step S12: N), the wireless communication unit 15 , Information indicating that the radio base station could not be detected is output to the search target selection unit 14. The search target selection unit 14 outputs information instructing the radio wave clock unit 11 to receive the standard radio wave via the position detection unit 12 (step S13A).

  When the radio clock unit 11 receives a standard radio wave (step S13A: Y), the radio clock unit 11 receives information included in the standard radio wave received by the position detection unit 12 and information indicating the frequency of the standard radio wave from the position detection unit 12. Output to. The position detection unit 12 determines the position where the mobile communication terminal 1A is present, for example, the country or region, based on the information included in the standard radio wave input from the radio clock unit 11 and the information indicating the frequency of the standard radio wave. Identify as information. Further, the position detector 12 outputs the specified position information to the search target selector 14A (step S14A).

  The search target selection unit 14A reads out and selects cell search target information corresponding to the position information input from the position detection unit 12 from the target information storage unit 13 (step S15A).

  On the other hand, when the radio clock unit 11 cannot receive the standard radio wave (step S13A: N), the radio clock unit 11 outputs information indicating that the standard radio wave cannot be received to the position detection unit 12. When the position detection unit 12 receives information indicating that the standard radio wave input from the radio wave clock unit 11 cannot be received, the position detection unit 12 outputs information indicating that the position information cannot be obtained to the search target selection unit 14. To do. When information indicating that position information cannot be obtained from the position detection unit 12 is input to the search target selection unit 14, the communication method and frequency range of all the mobile communication systems supported by the wireless communication unit 15 are set in the cell. The search target is selected (step S16A).

  Subsequently, the search target selection unit 14A determines whether or not timer expiration information is input from the timer unit 16 (step S17A).

If the search target selection unit 14A does not receive timer expiration information from the timer unit 16 (step S17A: N), the search target selection unit 14A outputs the selected cell search target information to the wireless communication unit 15. When the cell search target information is input from the search target selection unit 14A, the radio communication unit 15 performs a cell search based on the input cell search target information (step S18A).
If all frequencies are selected in step S16A, searching for all frequencies every time in step S18A increases power consumption. Therefore, the communication method and frequency of the mobile communication system that has been in the area immediately before is searched. A cell search may be performed only on the range.

  On the other hand, when the search target selection unit 14A receives information indicating that the timer has expired from the timer unit 16 (step S17A: Y), the search target selection unit 14A corresponds to the wireless communication unit 15. The communication method and frequency range of all mobile communication systems are selected, and the selected communication method and frequency range are output to the wireless communication unit 15 as cell search target information. The wireless communication unit 15 performs a cell search based on the cell search target information input from the search target selection unit 14A (step S19A). Here, in step S19A, the communication method and frequency range selected by the search target selection unit 14A are the same as the communication method and frequency range selected by the search target selection unit 14A in step S11A and the search target selection unit 14A in step S16A. It is.

  In step S18A or step S19A, when the radio communication unit 15 detects a communicable radio base station, that is, in the case of a located state (step S20A: Y), the radio communication unit 15 detects the radio base station. The communication method and frequency range used in the above are output to the search target selection unit 14A. When the search target selection unit 14A determines that the communication method and frequency range input from the wireless communication unit 15 are associated with the current position information and are not stored in the target information storage unit 13, the search target selection unit 14A The communication method and the frequency range are associated with each other, and are written and stored in the target information storage unit 13 as cell search target information (step S21A).

  The mobile communication terminal 1 enters a service area state and ends the cell search operation (end).

  On the other hand, in step S18A or step S19A, if the wireless communication unit 15 cannot detect a communicable radio base station, that is, if it is in an out-of-service state (step S20: N), the mobile communication terminal 1 is in an out-of-service state. The operation after step S17A is performed again at regular time intervals until the area is in the service area. That is, the wireless communication unit 15 performs a cell search for the communication method and frequency range selected as the cell search target information in steps S15A and S16A (step S18A), or all the mobile units to which the wireless communication unit 15 corresponds. A cell search is performed for the communication method and the frequency range of the communication system (step S19A), and it is repeatedly determined whether or not a communicable radio base station has been detected (step S20A) until the in-zone state is reached.

As described above, the mobile communication terminal 1A performs a cell search.
Compared with the mobile communication terminal 1 of the first embodiment, the mobile communication terminal 1A of the second embodiment includes only the cell search target information selected by the standard radio wave received once by providing the timer unit 16. In addition, the cell search is periodically performed for communication methods and frequency ranges used in all mobile communication systems supported by the wireless communication unit 15. Thereby, even when the mobile communication terminal 1A moves to a country or region that does not correspond to the selected cell search target information during the cell search, the cell search can be performed. Further, even if the search target information stored in the target information storage unit 13 is different from the current mobile communication system provision state due to a change in the provider providing the mobile communication system, the mobile object The communication terminal 1A can perform a cell search.

In addition, although the state immediately after starting to supply power to the mobile communication terminal 1A has been described, all mobile communication has been started from the location state in any of a plurality of mobile communication systems supported by the mobile communication terminal 1A. A similar cell search operation is performed even when the system is out of service.
Further, in step S11A, the mobile communication system that has been in the area immediately before without performing a cell search for the communication method and frequency range used in all the mobile communication systems supported by the mobile communication terminal 1A. Only the communication method and frequency range used may be targeted for cell search, and cell search may be performed. This is because, when the mobile communication terminal 1A is moving, even if the mobile communication terminal 1A is once out of service, it may be in the service area again. As described above, by limiting the communication method and frequency range to be subjected to the cell search, it is possible to suppress the time and power consumption required for the cell search.

  Further, in the case of the out-of-service state in step S20A, the operation after step S17A may be performed after a predetermined time has elapsed without immediately repeating the operation after step S17A. At that time, the mobile communication terminal 1A includes a timer different from the timer unit 16, and the radio communication unit 15 performs a cell search again after detecting the elapse of a predetermined time. As a result, the frequency of cell search can be suppressed, and power consumption due to cell search can be suppressed.

  Note that, instead of the timer unit 16, the number of cell searches performed in step S18A is counted, and the timing for performing the cell search performed in step S19A for each predetermined cell search time interval is set as the search target selection unit 14A. May be provided with a counter unit that outputs the data.

(Third embodiment)
FIG. 5 is a schematic block diagram showing the internal configuration of the mobile communication terminal 2 according to the third embodiment. The mobile communication terminal 2 includes a radio clock unit 21, a position detection unit 22, a target information storage unit 23, a search target selection unit 24, a wireless communication unit 25, and an antenna 27.

The radio clock unit 21 has a function of receiving a predetermined one of standard frequency time signal radio waves (hereinafter, standard radio waves) transmitted as a national standard or an international standard, and information included in the received standard radio waves. , And information indicating the frequency of the received standard radio wave is output to the position detector 22. Note that the standard radio wave includes a time code in the time format of each region, and whether the mobile radio terminal 2 is present in a specific country or region by receiving the standard radio wave is determined. Can be determined.
The position detection unit 22 determines whether or not the mobile communication terminal 2 exists in a specific country or region from the information included in the standard radio wave input from the radio clock unit 21 and the frequency of the standard radio wave as position information. To do. Further, the position detection unit 22 outputs the determined position information to the search target selection unit 24.

  The target information storage unit 23 stores cell search target information for specific position information, cell search target information for other than specific position information, and two cell search target information.

  The search target selection unit 24 reads cell search target information corresponding to the position information input from the position detection unit 22 from the target information storage unit 23, and outputs the cell search target information to the wireless communication unit 25. Further, if the search target selection unit 24 determines that the communication method and frequency range input from the wireless communication unit 25 and the position information input from the position detection unit 22 are not stored in the target information storage unit 23. The search target selection unit 24 associates the position information with the input communication method and frequency range, and writes the information as cell search target information in the target information storage unit 23 for addition.

  The wireless communication unit 25 has a function of performing communication with a plurality of mobile communication systems. For example, the wireless communication unit 25 is compatible with W-CDMA and GSM communication methods and has a generally known function of transmitting and receiving information via the antenna 27 in a plurality of frequency ranges. Further, the radio communication unit 25 performs a cell search for detecting a communicable radio base station via the antenna 27 based on the communication method and frequency range input from the search target selection unit 24. Further, the radio communication unit 25 outputs to the search target selection unit 24 whether or not the radio base station has been detected, and selects the communication method and frequency range corresponding to the radio base station obtained as a result of the cell search. To the unit 24.

  The mobile communication terminal 2 includes, for example, a radio clock unit 21 having a function of receiving a specific small number of standard radio waves that can be received in Japan, so that whether or not the position detection unit 22 exists in Japan. Make a decision. The search target selection unit 24 reads and selects cell search target information for domestic use from the target information storage unit 23, and causes the radio communication unit 25 to perform a cell search using the selected cell search target information. In addition, when it exists outside Japan, the search target selection unit 24 reads out and selects cell search target information for use outside Japan from the target information storage unit 23, and uses the selected cell search target information to perform radio communication unit 25. Let cell search.

  FIG. 6 is a flowchart showing a cell search operation performed by the mobile communication terminal 2 according to the third embodiment. The cell search operation shown in the figure is performed in an out-of-service state in which the mobile communication terminal 2 cannot receive radio waves from any radio base station immediately after power is supplied or cannot communicate with the radio base station. This is the operation to be performed. Hereinafter, the state immediately after starting to supply power to the mobile communication terminal 2 will be described.

  First, when the mobile communication terminal 2 starts to be supplied with power, the search target selection unit 24 determines all the movements to which the wireless communication unit 25 corresponds in order to determine whether or not the terminal itself is in the service area. The communication method and frequency range used in the body communication system are selected as cell search target information, and the selected cell search target information is output to the wireless communication unit 25 (step S21).

  When the cell search target information is input from the search target selection unit 24, the wireless communication unit 25 performs a cell search for the communication method and frequency range included in the input cell search target information, and is the in-service area state? It is determined whether or not (step S22).

When the wireless communication unit 25 detects a communicable wireless base station, if it is in the located state (step S22: Y), the operation of step S29 described later is performed.
The mobile communication terminal 1 ends the cell search (end).

  If the wireless communication unit 25 cannot detect a communicable wireless base station, that is, if it is out of service (step S22: N), the wireless communication unit 25 searches for information indicating that the wireless base station could not be detected. The data is output to the selection unit 24. The search target selection unit 24 outputs information instructing the radio wave clock unit 21 to receive a predetermined standard radio wave via the position detection unit 22 (step S23).

  If the radio clock unit 21 cannot receive a predetermined standard radio wave (step S23: N), the radio clock unit 21 outputs information indicating that the standard radio wave could not be received to the position detection unit 22. When the position detection unit 22 receives information indicating that the standard radio wave input from the radio wave clock unit 21 has not been received, the position detection unit 22 outputs the information to the search target selection unit 24. The search target selection unit 24 uses the information indicating that the standard radio wave input from the position detection unit 22 could not be received, the country or region where the terminal is located, the predetermined country or region and the position of the terminal. Is determined to be different (step S23: N), cell search target information associated with position information indicating other than a predetermined country or region is read from the target information storage unit 23 and selected (step S24).

  When the radio clock unit 21 receives a predetermined standard radio wave (step S23: Y), the radio clock unit 21 positions the information included in the standard radio wave received by the position detection unit 22 and the information indicating the frequency of the standard radio wave. Output to the detector 22. The position detection unit 22 determines whether or not the mobile communication terminal 1 exists in a predetermined country or region based on information included in the standard radio wave input from the radio clock unit 21 and information indicating the frequency of the standard radio wave. To determine the position information. Further, the position detection unit 22 outputs the position information to the search target selection unit 24 (step S25).

  When the search target selection unit 24 determines that the country or region indicated by the position information input from the position detection unit 22 matches the predetermined country or region, the search target selection unit 24 uses the position information indicating the predetermined country or region. The associated cell search target information is read from the target information storage unit 23 and selected (step S26).

  The search target selection unit 24 outputs the cell search target information selected in step S24 or step S26 to the wireless communication unit 25. When the cell search target information is input from the search target selection unit 24, the wireless communication unit 25 performs a cell search based on the cell search target information (step S27).

  As a result of the cell search in step S27, if a communicable radio base station can be detected (step S28: Y), the radio communication unit 25 selects a communication method and frequency range corresponding to the detected radio base station as a search target. To the unit 24. When the search target selection unit 24 determines that the communication method and frequency range input from the wireless communication unit 25 are associated with the current position information and are not stored in the target information storage unit 23, the search target selection unit 24 Then, the communication method and the frequency range are associated and written as cell search target information, and stored in the target information storage unit 23 (step S29).

  The mobile communication terminal 2 enters a service area and ends the cell search operation (end).

As a result of the cell search in step S27, if a communicable radio base station cannot be detected (N in step S28), the mobile communication terminal 2 is in an out-of-service state, so the operations in and after step S27 are in the in-service state. Until again. That is, the radio communication unit 25 performs a cell search for the communication method and frequency range selected as the cell search target information in steps S24 and S26 (step S27), and whether or not a communicable radio base station has been detected. That is, the determination of whether or not being in the service area (step S28) is repeated until the service area is reached.
If a radio base station cannot be detected for a certain period of time, all mobile communication systems and frequency ranges supported by the radio communication unit 25 may be selected as cell search target information.

As described above, the mobile communication terminal 2 performs a cell search.
Compared to the mobile communication terminal 1 of the first embodiment, the mobile communication terminal 2 stores two pieces of cell search target information corresponding to specific position information and other position information in the target information storage unit 23. It is configured to memorize. Thereby, compared with the mobile communication terminal 1 of 1st Embodiment and the mobile communication terminal 1A of 2nd Embodiment, the memory area required for the object information storage part 23 can be reduced. Further, since the radio clock unit 21 only needs to receive one specific standard radio wave, the circuit size of the radio clock unit 21 can be reduced. Furthermore, since only one country or region is specified for the position detection unit 22, the circuit size can be similarly reduced. As a result, it is possible to reduce the cost when the cell search function is implemented.

  The form such as the mobile communication terminal 2 is a form suitable for use in a mobile communication terminal that is used exclusively in Japan and has almost no opportunity to use outside Japan.

  When the radio clock unit 11 receives a plurality of standard radio waves, a standard radio wave having a strong radio wave intensity is selected and used. Further, when the radio clock unit 11 receives a plurality of standard radio waves, the cell search may be performed using cell search target information corresponding to a plurality of pieces of position information detected by the received standard radio waves.

  Note that the wireless communication unit 15 and the wireless communication unit 25 may have functions of a communication method such as the WiMAX method as well as the communication method of the W-CDMA method and the GSM method. In this case, the target information storage unit 13 records information including the communication scheme provided and the frequency range used for the communication scheme as the cell search target information.

  In the first to third embodiments, the communication method included in the cell search target information used when performing cell search may be the same and only the frequency range may be different. For example, the GSM method is used as a communication method for cell search, and only the frequency range is different. Further, the cell search target information may include only the communication method or the frequency range. When only the communication method is included, only one communication method is used in the mobile communication system supported by the wireless communication units 15 and 25, and only the frequency range is different. When only the frequency is included, the frequency range used in the mobile communication system supported by the wireless communication units 15 and 25 is the same and the communication method is different.

  In addition, in the above first to third embodiments, search target information is added (steps S19, S21A, and S31). In that case, there is no need to prepare an area for storing additional search target information in the target information storage units 13 and 23, and the size and cost required for the mobile communication terminal can be reduced by reducing the storage area. be able to.

  Further, in the first to third embodiments, instead of receiving the standard radio wave and specifying the country or region, the country or region is determined using GPS (Global Positioning System). You may specify.

  The search target selection units 14, 14A, 24 and the position detection units 12, 22 described above may have a computer system therein. In this case, the cell search process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The present invention is suitable for use in a mobile communication terminal such as a mobile phone, but is not limited to this.

It is a schematic block diagram which shows the structure of the mobile communication terminal in 1st Embodiment. It is a flowchart which shows operation | movement of the mobile communication terminal in 1st Embodiment. It is a schematic block diagram which shows the structure of the mobile communication terminal in 2nd Embodiment. It is a flowchart which shows operation | movement of the mobile communication terminal in 2nd Embodiment. It is a schematic block diagram which shows the structure of the mobile communication terminal in 3rd Embodiment. It is a flowchart which shows operation | movement of the mobile communication terminal in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mobile communication terminal, 1A ... Mobile communication terminal 11 ... Radio clock part, 12 ... Position detection part, 13 ... Object information storage part 14 ... Search object selection part, 14A ... Search object selection part 15 ... Wireless communication part, DESCRIPTION OF SYMBOLS 16 ... Timer part, 17 ... Antenna 2 ... Mobile communication terminal 21 ... Radio wave clock part, 22 ... Position detection part, 23 ... Object information storage part 24 ... Search object selection part, 25 ... Wireless communication part, 27 ... Antenna

Claims (6)

A mobile communication terminal that performs wireless communication in a plurality of mobile communication systems with different communication methods or frequency ranges,
A radio clock unit that receives standard frequency time signals transmitted from different standard frequency time signal stations in each country or region;
A position detection unit that outputs, as position information, the position of the terminal that is identified based on the standard frequency time signal received by the radio clock unit;
Cell search target information used for each of the plurality of mobile communication systems, a target information storage unit stored in association with the position information;
A search target for selecting, from the target information storage unit, the cell search target information used when performing a cell search for detecting a radio base station of the mobile communication system based on the position information input from the position detection unit. A selection section;
Using the cell search target information selected by the search target selection unit, a radio communication unit that performs the cell search;
A mobile communication terminal comprising: The search target selection unit further selects the communication method or the frequency range used in all the plurality of mobile communication systems supported by the radio communication unit at regular time intervals, and selects the cell search target. The mobile communication terminal according to claim 1, wherein the mobile communication terminal outputs the information to the wireless communication unit. When the radio communication unit detects the radio base station by the cell search, the cell search target information used at that time is output to the search target selection unit,
The search target selection unit is associated with the position information input from the position detection unit, and when the cell search target information input from the wireless communication unit is not stored, the search target selection unit The mobile communication terminal according to claim 1, wherein the cell search target information is associated with the cell search target information, and is written and stored in the target information storage unit. The mobile radio communication terminal according to any one of claims 1 to 3, wherein the radio clock unit receives standard frequency time signal waves transmitted from a specific small number of standard frequency time signal stations. The mobile communication terminal according to any one of claims 1 to 4, wherein the cell search target information is information including information on the communication method or the frequency range. Wireless communication is performed in a plurality of mobile communication systems having different communication methods or frequency ranges, and cell search target information used for each of the plurality of mobile communication systems is stored in association with position information indicating the position of the terminal itself. A cell search method in a mobile communication terminal comprising a target information storage unit, comprising:
The process of receiving the standard frequency time signal transmitted from the standard frequency time signal station, which is different for each country or region,
A process in which the position detection unit outputs the position of the terminal identified based on the standard frequency time signal received by the radio clock unit as position information;
A process in which a search target selection unit selects, from the target information storage unit, the cell search target information used when performing a cell search for detecting a radio base station based on the position information input from the position detection unit; ,
A step in which a radio communication unit performs the cell search using the cell search target information selected by the search target selection unit;
A cell search method comprising:

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