JP2010232956A - Mobile terminal, base station, mobile communication system, and communication control method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the power consumption of a mobile terminal when retrieving a base station. <P>SOLUTION: The base station 10 configuring the mobile communication system 1 includes geographical information (out-of-service area geographical information) 101 outside a series of service areas formed together with the other base stations in the intrinsic information 102 of the present base station and wirelessly transmits it. The mobile terminal 20 wirelessly receives the intrinsic information 102 from the base station 10, extracts the out-of-service area geographical information 101 from the intrinsic information 102 and stores it. When moving out of the service area, the mobile terminal 20 periodically acquires the position information 105 of the present terminal by using radio signals 4 for positioning, received from a GPS satellite 3. Then, when determining that the present terminal has moved to the vicinity of the service area based on the position information 105 and the out-of-service area geographical information 101, the mobile terminal 20 retrieves a connectable base station. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mobile terminal, a base station, a mobile communication system, and a communication control method and program, and more particularly to a technique for reducing power consumption of a mobile terminal when searching for a base station.

  In a general mobile communication system, when a mobile terminal such as a mobile phone moves out of a series of service areas (out-of-service area) formed by a plurality of base stations, it searches for a connectable base station.

  More specifically, when searching for a base station, first, the mobile terminal searches for a radio channel (broadcast channel) broadcast by the base station. At this time, the mobile terminal searches all radio channels that the base station can use as broadcast channels in all frequency bands applied to the mobile communication system.

  Next, the mobile terminal determines whether an effective radio channel with good radio wave quality (a radio channel whose radio wave quality exceeds a predetermined standard) has been detected. As a result, when it is determined that an effective radio channel has been detected, the mobile terminal considers that the mobile terminal is located within the base station (in the cell) of the base station using the radio channel.

  On the other hand, if it is determined that an effective radio channel has not been detected, the mobile terminal considers that the mobile terminal is still located in the out-of-service area and repeatedly executes base station search. That is, the mobile terminal performs a base station search even when it is located in a complete out-of-service area. For this reason, a general mobile terminal has a problem that power such as a battery is wasted.

  For example, Patent Documents 1 to 4 describe mobile terminals that deal with this problem.

  Among these, the mobile terminal described in Patent Document 1 changes the base station search execution interval in accordance with the distance between the terminal and the base station. More specifically, the mobile terminal compares the distance with the base station installation position information stored in advance and the position information of the terminal measured by the GPS (Global Positioning System) function. calculate.

  Also, the mobile terminal described in Patent Document 2 compares the distance between the own terminal and the base station calculated in the same manner as Patent Document 1 described above and a predetermined distance (threshold), and according to the comparison result. Controls stop or restart of base station search.

  Further, the mobile terminal described in Patent Document 3 stores all the position information of the own terminal measured during connection with the base station, and stops the wireless communication function when moving to an out-of-service area. Then, when the stored location information includes the current location information of the own terminal newly measured by the GPS function, the mobile terminal determines that the mobile terminal has returned to the service area and restarts the wireless communication function. Perform base station search.

  Further, the mobile terminal described in Patent Document 4 stores the position information of the terminal measured by the GPS function in the out-of-service area, and when moving to the out-of-service area again, the mobile terminal newly stores the stored position information and the GPS function. Compare with the measured position information. As a result, when both pieces of position information match, the mobile terminal stops the wireless communication function (does not perform base station search).

  However, the above-described Patent Documents 1 and 2 have a problem in that the application area of the mobile terminal (area in which the mobile terminal can perform communication) is restricted. This is because it is practically difficult to store the location information of all of a huge number of base stations installed at home and abroad in limited storage resources (memory, etc.) within the mobile terminal. .

  In addition, the above-mentioned Patent Document 3 has a problem that a case where the mobile terminal cannot resume communication with the base station occurs in addition to the restriction of the application area. This is because if the mobile terminal does not move again to the stored location (the same location that communicated with the base station in the past), the wireless communication function is stopped even if it returns to the range (other location). Because it will remain. Similarly, when moving from a non-service area to a new base station, the wireless communication function remains stopped.

  Furthermore, the above-mentioned Patent Document 4 has a problem that in a non-service area where a mobile terminal stays for the first time, a base station search is performed in the same manner as a general mobile terminal, and power consumption is not reduced at all.

  A mobile terminal that further copes with these problems is described in Patent Document 5, for example.

  When the mobile terminal described in Patent Document 5 moves to an out-of-service area, the mobile terminal compares the position information of its own terminal that is periodically measured by the GPS function. As a result, when the change of the position information is not detected for a predetermined time, the mobile terminal determines that the mobile terminal stays in the out-of-service area and extends the base station search execution interval.

JP 2003-163627 A JP 2004-320576 A JP 2005-236835 A JP 2006-246342 A JP 2007-259198 A

  However, the above-mentioned Patent Document 5 has a problem that the effect of reducing power consumption cannot be obtained sufficiently. This is because the base station search continues to be executed while the mobile terminal stays in the out-of-service area, although the execution frequency decreases.

  A mobile terminal according to an aspect of the present invention includes: a reception unit that wirelessly receives unique information necessary for connection to the one base station from one base station; and the one base station and the other from the unique information. A storage unit that extracts and stores geographical information outside a series of service areas formed by a base station of the mobile station, and when the terminal moves outside the service area, it uses radio signals received from GPS satellites to An acquisition unit that periodically acquires location information of a terminal, and a search unit that searches for a connectable base station when it is determined that the terminal has moved to the vicinity of the service area based on the location information and the geographic information And comprising.

  In addition, the base station according to one aspect of the present invention includes a storage unit that stores geographic information outside a series of service areas formed together with other base stations, and includes the geographic information in unique information of the own base station and transmits wirelessly. A sending unit.

  The mobile communication system according to one aspect of the present invention includes a base station that wirelessly transmits geographic information outside a series of service areas formed with other base stations included in unique information of the own base station, and the base The unique information is wirelessly received from the station, and the geographic information is extracted from the unique information and stored. When the own terminal moves out of the service area, the own terminal uses the radio signal received from the GPS satellite. A mobile terminal that periodically acquires location information and searches for a connectable base station when it is determined that the terminal has moved to the vicinity of the service area based on the location information and the geographic information.

  A communication control method according to an aspect of the present invention provides a communication control method in a mobile terminal. This communication control method wirelessly receives unique information necessary for connection with the one base station from one base station, and is formed by the one base station and another base station from the unique information. Geographic information outside a series of service areas is extracted and stored, and when the mobile terminal moves outside the service area, the location information of the mobile terminal is periodically acquired using a radio signal received from a GPS satellite. If it is determined that the mobile terminal has moved to the vicinity of the service area based on the location information and the geographic information, a connectable base station is searched.

  A communication control method according to another aspect of the present invention provides a communication control method in a base station. In this communication control method, geographic information outside a series of service areas formed with other base stations is stored, and the geographic information is included in unique information of the base station and transmitted wirelessly.

  In addition, the communication control program according to an aspect of the present invention includes a process of wirelessly receiving, from a base station, unique information necessary for connection with the one base station, to the mobile terminal, from the unique information, A process of extracting and storing geographic information outside a series of service areas formed by one base station and another base station, and a radio received from a GPS satellite when the mobile terminal moves outside the service area Connection is possible when it is determined that the mobile terminal has moved to the vicinity of the service area based on the processing for periodically acquiring the location information of the mobile terminal using a signal and the location information and the geographic information And a process of searching for a base station.

  Furthermore, a communication control program according to another aspect of the present invention includes a process for storing geographic information outside a series of service areas formed together with other base stations in the base station, and storing the geographic information in a unique manner of the base station. And processing for wireless transmission included in the information.

  That is, the mobile terminal uses the geographical information of the out-of-service area broadcast from the base station, and executes the base station search only when the mobile terminal is located in the out-of-service area and the vicinity of the service area. Do not perform base station search. For this reason, it is possible to significantly reduce the power consumption of the mobile terminal as compared with Patent Document 5 described above.

  Further, since only the geographical information of the out-of-service area is stored (that is, the minimum necessary storage resource is used), there is no restriction of the application area such as the mobile terminal described in Patent Documents 1 to 3 above. Furthermore, unlike the above-mentioned Patent Document 4, the effect of reducing power consumption can be obtained regardless of whether or not the mobile terminal stays in the out-of-service area for the first time.

  According to the present invention, it is possible to further reduce the power consumption of a mobile terminal when searching for a base station. For this reason, it is possible to extend the usable time of a mobile terminal and to improve a user's convenience. It is also possible to reduce the capacity of the battery or the like, thereby reducing the cost and size of the mobile terminal.

It is the block diagram which showed the structural example of the mobile terminal and base station which concern on Embodiment 1 of this invention, and the mobile communication system to which these are applied. It is the flowchart figure which showed the example of whole operation | movement of the mobile terminal which concerns on Embodiment 1 of this invention. It is the flowchart figure which showed an example of the re-movement determination process to the service area vicinity in the mobile terminal which concerns on Embodiment 1 of this invention. It is the flowchart figure which showed the other example of the re-movement determination process to the service area vicinity in the mobile terminal which concerns on Embodiment 1 of this invention. It is the block diagram which showed the structural example of the mobile terminal and base station which concern on Embodiment 2 of this invention, and the mobile communication system to which these are applied.

  Embodiments 1 and 2 of a mobile terminal, a base station, and a mobile communication system to which these are applied according to the present invention will be described below with reference to FIGS. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary for the sake of clarity.

[Embodiment 1]
A mobile communication system 1 according to the present embodiment shown in FIG. 1 includes a base station 10 that forms a series of service areas together with other base stations (not shown), and within the base station 10 (within a cell). The mobile terminal 20 communicates with the base station 10 using the radio signal 2.

  Among these, the base station 10 stores the storage unit 11 that stores geographical information outside the service area (hereinafter referred to as out-of-service area geographical information) 101, and broadcast information generation that generates the broadcast information 102 including the out-of-service area geographical information 101. And a wireless transceiver 13 that modulates the notification information 102 and transmits it as a wireless signal 2. Note that the radio transceiver 13 modulates data (not shown) received from a core network including a radio control station, an exchange station, and the like, as in the case of a transceiver implemented in a general base station. 2 and a function of demodulating the radio signal 2 received from the mobile terminal 20 and transferring it to the core network.

  Here, the out-of-service area geographic information 101 is information on the boundary position between the service area and the out-of-service area (for example, the latitude, longitude, altitude, etc. of some of the boundary positions discontinuously selected from all the boundary positions). It is preferable that the configuration is included. In this case, in addition to the minimum necessary storage resources in the mobile terminal 20, the comparison process with the location information 105 described later in the mobile terminal 20 is simplified, and the processing load on the mobile terminal 20 can be reduced. The broadcast information 102 includes various information necessary for the mobile terminal 20 to connect to the base station 10 in addition to the out-of-service area geographic information 101. That is, information other than the out-of-service area geographic information 101 in the broadcast information 102 is the same as the broadcast information used by a general base station.

  Moreover, it is preferable that the broadcast information generating unit 12 includes the out-of-service area geographic information 101 in the broadcast information 102 only when a cell formed by the base station 10 forms an edge of the service area. In this case, a general base station can be used as it is for a base station that forms a cell outside the service area boundary, and thus the construction cost of the mobile communication system 1 can be reduced.

  On the other hand, the mobile terminal 20 includes a radio transceiver 21, a storage unit 22, a location information acquisition unit 23, a base station search unit 24, a reception level detection unit 25, and a coverage area determination unit 26.

  Among these, the radio transceiver 21 is similar to a transceiver implemented in a general mobile terminal, and has a function of demodulating the radio signal 2 received from the base station 10 and a communication control circuit (not shown) in the mobile terminal 20. ) Is modulated and transmitted as a radio signal 2 to the base station 10.

  Further, the reception level detection unit 25 detects the reception level 103 of the radio signal 2. The area determination unit 26 compares the reception level 103 output from the reception level detection unit 25 with a predetermined threshold level (not shown) to determine whether or not the mobile terminal 20 is located within the base station 10 range. Determine whether. In addition, the area determination unit 26 gives the determination result 104 to the position information acquisition unit 23 and the base station search unit 24, respectively. The area determination using the reception level 103 is an example, and the mobile terminal 20 may perform other known area determination.

  Further, the storage unit 22 extracts the out-of-service area geographic information 101 from the notification information 102 received by the wireless transceiver 21 and stores it in a register, a memory (not shown) or the like.

  Further, the position information acquisition unit 23 performs a predetermined calculation on the GPS receiver 231 that receives the positioning radio signal 4 from the GPS satellite 3 and the positioning radio signal 4, and thereby the position information 105 of the mobile terminal 20. A positioning unit 232 for obtaining Here, the positioning unit 232 controls the GPS receiver 231 and periodically acquires the position information 105 when the determination result 104 output from the range determination unit 26 indicates “out of range”.

  Furthermore, when the determination result 104 output from the range determination unit 26 indicates “out of range”, the base station search unit 24 outputs the out-of-service area geographic information 101 acquired from the storage unit 22 and the position information output from the positioning unit 232. 105, it is determined whether or not the mobile terminal 20 has moved again to the vicinity of the service area. In the following description, this determination process is referred to as a re-movement determination process. When the base station search unit 24 determines that the mobile terminal 20 has moved to the vicinity of the service area as a result of the re-moving determination process, the base station searching unit 24 controls the wireless transceiver 21 to perform base station search.

  Next, the operation of the mobile terminal 20 will be described in detail with reference to FIGS.

  As shown in FIG. 2, first, the radio transceiver 21 in the mobile terminal 20 receives the broadcast information 102 from the base station 10 (step S1). Subsequently, the area determination unit 26 determines whether the base station 10 is an effective base station as a communication partner of the mobile terminal 20 (step S2). More specifically, the area determination unit 26 determines whether or not the reception level 103 output from the reception level detection unit 25 is equal to or higher than a predetermined threshold level. As a result, when it is determined that the base station 10 is an effective base station, the area determination unit 26 causes the communication control circuit to execute a connection process to the base station 10 and thereby causes the mobile terminal 20 to transition to the area state. (Step S3). Thereby, desired radio communication is performed between the mobile terminal 20 and the base station 10.

  Moreover, the memory | storage part 22 extracts and memorize | stores out-of-service area geographic information 101 from the alerting | reporting information 102 received with the radio | wireless transmitter / receiver 21 (step S4).

  The reception level detection unit 25 periodically detects the reception level 103 of the wireless signal 2 (step S5). Then, the area determination unit 26 uses the reception level 103 to monitor the movement of the mobile terminal 20 to the outside area (step S6). More specifically, the area determination unit 26 determines that the mobile terminal 20 has moved to the out-of-service area when the reception level 103 falls below a predetermined threshold level and there is no other valid base station. At this time, the area determination unit 26 stops the connection process by the communication control circuit, and thus shifts the mobile terminal 20 to the out-of-area state (step S7). In addition, the area determination unit 26 gives the determination result 104 indicating “out of area” to the position information acquisition unit 23 and the base station search unit 24, respectively.

  The positioning unit 232 in the position information acquisition unit 23 controls the GPS receiver 231 to periodically acquire the position information 105 of the mobile terminal 20 (step S8).

  Further, the base station search unit 24, for example, based on the location information 105 output from the positioning unit 232 and the out-of-service area geographic information 101 stored in the storage unit 22, for example, a re-movement determination process (1) or (2) described later. ) Is executed (step S9). As a result, when it is determined that the mobile terminal 20 has moved to the vicinity of the service area (step S10), the base station search unit 24 controls the radio transceiver 21 to execute a base station search (step S11).

  On the other hand, when it is determined in step S10 that the mobile terminal 20 has not moved near the service area, the mobile terminal 20 executes steps S8 and S9 again.

  Hereinafter, re-movement determination processing examples (1) and (2) by the base station search unit 24 will be described with reference to FIGS. 3 and 4 respectively.

[Example of re-moving determination process (1)]
As shown in FIG. 3, first, the base station search unit 24 calculates a distance 106 between the current position of the mobile terminal 20 (that is, the latest position information 105) and the boundary position indicated by the out-of-service area geographic information 101. (Step S21).

  Then, the base station search unit 24 determines whether or not the distance 106 is equal to or less than a predetermined threshold (distance) (step S22). As a result, when the distance 106 ≦ threshold is satisfied, the base station search unit 24 determines that the mobile terminal 20 has moved to the vicinity of the service area (step S23).

  On the other hand, when the distance 106> threshold value is established, the base station search unit 24 determines that the mobile terminal 20 still remains in the out-of-service area (step S24).

[Example of re-moving determination process (2)]
As shown in FIG. 4, first, the base station search unit 24 predicts the destination position 107 of the mobile terminal 20 from the position information 105 (that is, the movement history of the mobile terminal 20) acquired over a certain period ( Step S31). More specifically, the base station search unit 24 estimates the movement destination position 107 by calculating the movement direction and movement speed of the mobile terminal 20 using the movement history.

  Then, the base station search unit 24 determines whether or not the destination position 107 exceeds the boundary position indicated in the out-of-service area geographic information 101, that is, whether or not the mobile terminal 20 can be more reliably expected to return to the service area. (Step S32). As a result, when the movement destination position 107 exceeds the boundary position, the base station search unit 24 determines that the mobile terminal 20 has moved to the vicinity of the service area (step S33).

On the other hand, when the movement destination position 107 does not exceed the boundary position, the base station search unit 24 determines that the mobile terminal 20 still remains in the out-of-service area (step S34).

  As described above, the mobile terminal 20 uses the comparison result between the location information 105 and the out-of-service area geographic information 101 to execute a base station search only when it is determined that the terminal is located in the out-of-service area and the vicinity of the service area. In other cases, the base station search is not executed. For this reason, the power consumption of the mobile terminal 20 can be significantly reduced.

  Further, the out-of-service area geographic information 101 is a relatively small amount of information such as the information on the boundary position between the service area and the out-of-service area, and does not require a large capacity for the storage resource in the mobile terminal 20. For this reason, the mobile terminal 20 is not restricted by its application area.

  Furthermore, since the out-of-service area geographic information 101 includes information on the out-of-service area where the mobile terminal 20 stays for the first time, the power consumption reduction effect described above is achieved when the mobile terminal 20 moves to any out-of-service area through any route. However, it can be obtained uniformly.

[Embodiment 2]
In the mobile communication system 1a according to the present embodiment shown in FIG. 5, the base station 10 has received out-of-service area geographic information stored in the storage unit 11 from the core network 5 in addition to the configuration shown in FIG. 1. The difference from the first embodiment is that the update unit 14 is updated with the latest out-of-service area geographic information 101. The configuration and operation of the mobile terminal 20 are the same as those in the first embodiment.

  According to the present embodiment, the mobile terminal 20 can always acquire the latest out-of-service area geographic information 101 even when a base station is added or removed or a service area is changed. Thus, the re-movement determination process described above can be executed more accurately. In addition, no modification is required in the configuration of the base station 10 itself regardless of any expansion or removal or service area change by the communication carrier.

  Note that the present invention is not limited to the above-described embodiments, and it is apparent that various modifications can be made by those skilled in the art based on the description of the scope of the claims.

  For example, each process shown in FIGS. 2 to 4 can be provided as a program for causing a mobile terminal to execute the processes. In this case, it is preferable to store the program in a storage medium such as a memory so that the processor in the mobile terminal can execute the program. Alternatively, the program may be provided as a plug-in to firmware incorporated in an existing communication control circuit.

  Further, it is also possible to provide a program for causing the base station to execute the out-of-service area geographic information transmission process shown in FIG. 1 and the out-of-service area geographic information update process shown in FIG. In this case, it is preferable to store the program in a storage medium such as a memory so that the processor in the base station can execute it. Alternatively, the program may be provided as a plug-in to firmware incorporated in an existing communication control circuit.

DESCRIPTION OF SYMBOLS 1, 1a Mobile communication system 2 Radio signal 3 GPS satellite 4 Positioning radio signal 10 Base station 11, 22 Storage unit 12 Broadcast information generation unit 13, 21 Radio transceiver 14 Update unit 20 Mobile terminal 23 Location information acquisition unit 24 Base Station search unit 25 Reception level detection unit 26 Area determination unit 101 Out-of-service area geographic information 102 Broadcast information 103 Reception level 104 Determination result 105 Position information 106 Distance 107 Destination position 231 GPS receiver 232 Positioning unit

Claims (17)

A receiving unit for wirelessly receiving unique information necessary for connection with the one base station from one base station;
A storage unit for extracting and storing geographical information outside a series of service areas formed by the one base station and another base station from the unique information;
An acquisition unit that periodically acquires location information of the terminal using a radio signal received from a GPS (Global Positioning System) satellite when the terminal moves outside the service area;
Based on the location information and the geographic information, if it is determined that the terminal has moved to the vicinity of the service area, a search unit for searching for a connectable base station,
Mobile terminal equipped with. In claim 1,
The geographic information indicates a boundary position between the service area and the external area;
The mobile terminal, wherein the search unit determines that the mobile terminal has moved to the vicinity of the service area when a distance between the current position of the mobile terminal and the boundary position is equal to or less than a predetermined distance. . In claim 1,
The geographic information indicates a boundary position between the service area and the external area;
The search unit predicts a destination position of the terminal based on position information acquired over a certain period, and the terminal moves to the vicinity of the service area when the destination position exceeds the boundary position. A mobile terminal characterized in that it is determined that it has been performed. A storage unit for storing geographical information outside a series of service areas formed together with other base stations;
A sending unit that wirelessly sends the geographical information including the unique information of the base station;
Base station equipped with. In claim 4,
The base station characterized in that the sending unit includes the geographic information in the specific information only when the base station forms an edge of the service area. In claim 4 or 5,
The base station characterized in that the geographic information indicates a boundary position between the service area and its external area. In any one of Claims 4-6,
The base station further comprising an update unit for updating the geographic information with geographic information received from outside. A base station that wirelessly transmits geographic information outside of a series of service areas formed with other base stations included in its own base station specific information,
The unique information is wirelessly received from the base station, and the geographic information is extracted from the unique information and stored. When the own terminal moves out of the service area, it uses the wireless signal received from the GPS satellite. If the location information of the terminal is periodically acquired and it is determined that the terminal has moved to the vicinity of the service area based on the location information and the geographic information, a mobile terminal that searches for a connectable base station,
A mobile communication system comprising: A communication control method in a mobile terminal,
From one base station, wirelessly receive unique information necessary for connection with the one base station,
Extracting and storing geographical information outside the series of service areas formed by the one base station and other base stations from the unique information,
When the mobile terminal moves out of the service area, using the radio signal received from the GPS satellite, periodically obtain the location information of the mobile terminal,
A communication control method for searching for a connectable base station when it is determined that the mobile terminal has moved to the vicinity of the service area based on the location information and the geographic information. In claim 9,
As the geographical information, information indicating a boundary position between the service area and the external area is used.
A communication control method, comprising: determining that the mobile terminal has moved to the vicinity of the service area when a distance between a current position of the mobile terminal and the boundary position is equal to or less than a predetermined distance. In claim 9,
As the geographical information, information indicating a boundary position between the service area and the external area is used.
A destination position of the mobile terminal is predicted based on position information acquired over a certain period, and when the destination position exceeds the boundary position, it is determined that the mobile terminal has moved near the service area. A communication control method characterized by that. A communication control method in a base station,
Stores geographic information outside the set of service areas that it forms with other base stations,
A communication control method in which the geographic information is included in unique information of the base station and transmitted wirelessly. In claim 12,
The communication control method characterized by including the geographic information in the unique information only when the base station forms an edge of the service area. In claim 12 or 13,
A communication control method characterized in that information indicating a boundary position between the service area and its external area is used as the geographic information. In any one of Claims 12-14,
A communication control method, wherein the geographic information is updated with geographic information received from outside. On the mobile device,
A process of wirelessly receiving unique information necessary for connection with the one base station from one base station;
Processing for extracting and storing geographical information outside a series of service areas formed by the one base station and another base station from the unique information;
When the mobile terminal has moved out of the service area, using a radio signal received from a GPS satellite, processing to periodically acquire the location information of the mobile terminal;
When it is determined that the mobile terminal has moved to the vicinity of the service area based on the location information and the geographic information, a process of searching for a connectable base station;
Communication control program to execute. To the base station,
Storing geographic information outside a set of service areas formed with other base stations;
A process of wirelessly sending the geographic information included in the unique information of the base station;
Communication control program to execute.

Images