| 摘要 |
PROBLEM TO BE SOLVED: To enable a user who has a mobile terminal, to know in advance whether or not he is going to get out of a communication range. SOLUTION: In a mobile terminal 11, present location information is periodically calculated by a location calculating part 15, and that location information is transmitted to an advance notice server 1 against leaving communication range. A control part 2 in the advance notice server 1 against leaving communication range stores the received location information in a location information history database 4. Besides, the location of the mobile terminal 11 after the lapse of a fixed time is predicted on the basis of the history of the location information stored in the location information history database 4 and map information stored in a map database 5. When the location is out of the communication range, the control part 2 transmits a notice of advance announcement that the mobile terminal is going out of the communication range, to the mobile terminal 11. When the mobile terminal 11 changes its advancing direction thereafter and the predicted location is settled within the communication range, a message indicating that there is no danger of getting out of the communication range, is transmitted to the mobile terminal 11. COPYRIGHT: (C)2005,JPO&NCIPI
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