JP2972771B1 - Method for preventing unauthorized use of identification information and mobile communication network - Google Patents

Abstract

A method and apparatus for preventing unauthorized use of identification information that can effectively monitor and prevent unauthorized use of a credit card, a mobile communication terminal, and the like without requiring addition of a large-scale device or the like. Provide a web. SOLUTION: A user is assigned a unique identification information to each of them in advance, and a user from any of a plurality of user identification means capable of performing various transaction operations via any of a plurality of terminal devices connected to a host computer. When a confirmation request is issued, the information of the last used terminal device and the use end time are read from the use history database with respect to the user identification means, and from the last used terminal device to the terminal device for which the user confirmation request was issued. If the time required to move from the terminal device used last by the user identification means to the terminal device for which the user confirmation request was issued exceeds the shortest travel time, Only various transaction operations by the user identification means are permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing unauthorized use of identification information for preventing unauthorized use of a portable telephone, a car telephone, a wireless information terminal, and the like, and a mobile communication network.

[0002]

2. Description of the Related Art In recent years, with the spread of mobile telephone terminals such as mobile telephones and car telephones, many users have come to use such mobile telephone terminals. Under such circumstances, there has been a problem that the identification information of the mobile phone of the authorized subscriber is illegally copied and used.

[0003] In a mobile telephone or the like, identification information unique to each mobile telephone terminal or subscriber is sent to an exchange in order to manage the location information of this mobile telephone terminal and the billing of a call charge. ing.

On the other hand, the switching center accesses the subscriber database based on the identification information to confirm whether the subscriber is a legitimate subscriber, and when the subscriber is determined to be a legitimate subscriber, enables communication. .

[0005]

When such a procedure is used, outgoing information from the mobile telephone terminal is received to decode the identification information, or the identification information is read out from the mobile telephone terminal by another method. Such actions are possible.
Therefore, there is a possibility that unauthorized communication may be performed by porting the identification information to another mobile telephone terminal.

To solve such a problem, for example, there is one disclosed in Japanese Patent Publication No. Hei 7-24434 and one disclosed in Japanese Patent No. 2555205 (Japanese Patent Laid-Open No. 6-69879).

[0007] However, the conventional fraud monitoring requires a complicated and large-scale configuration, and when it is used for purposes other than the above-described mobile communication, a large change in the configuration is required, and various problems are caused. was there.

The present invention has been made in view of such a background, and does not require a large-scale addition of devices and the like, and effectively monitors and prevents unauthorized use of credit cards and mobile communication terminals. It is an object of the present invention to provide a method of preventing unauthorized use of identification information and a mobile communication network.

[0009]

In order to solve the above-mentioned problems, according to the present invention, a plurality of terminals are each assigned a unique identification information in advance and connected to a host computer. When a user confirmation request is issued from any of a plurality of user identification means capable of performing various transaction operations via any of the devices, information on the last used terminal device with respect to the user identification means, The use end time is read from the use history database, and the shortest travel time from the last used terminal device to the terminal device for which the user confirmation request has been issued is read from the transportation database, and the user identification means is finally used. Only when the time required to move from the used terminal device to the terminal device for which the user confirmation request has been issued exceeds the shortest travel time, And permits the various transaction operation by the user identification unit. In the invention according to claim 2, in the method for preventing unauthorized use of identification information according to claim 1, when the various transaction operations related to the user confirmation request are not permitted, The number of times the user confirmation request issued by the user identification means has been rejected is read from the confirmation count database, and if the number of times the rejection has exceeded the predetermined number, the user identification means User information corresponding to the unique identification information to be notified is read from the user database, and the identification information unique to the user identification means corresponding to the read user information is changed. In the invention according to claim 3, in the method for preventing unauthorized use of identification information according to any one of claims 1 and 2, when a user confirmation request is issued from the user identification means, Only when the identification information unique to the user identification means is present in the identification information database, the user identification means is required to move from the last used terminal device to the terminal device to which the user confirmation request was issued. It is characterized in that it is confirmed whether or not the set time exceeds the shortest travel time. Further, in the invention according to claim 4, the exchange connected to the public communication network is assigned unique identification information to each of the exchanges in advance, and the exchange via any one of a plurality of base stations. From a calling terminal that is any of a plurality of mobile communication terminals that can be connected to a public communication network to a receiving base station that is connected to the exchange and is any of the plurality of base stations each having a predetermined communication range. When a communication request is issued to the originating terminal, information on the last base station, which is the last communication partner, and the communication end time are read from the communication history database, and the shortest travel time from the last base station to the destination base station is determined. The time required for the calling terminal to move from the communication range of the final base station to the communication range of the called base station is read out from the transportation database, and Only if it exceeds the time and permits communication with the incoming base station and the calling terminal. Also,
According to a fifth aspect of the present invention, in the method for preventing unauthorized use of identification information according to the fourth aspect, the switching center transmits a communication request to the destination base station from the originating terminal. When the communication is not permitted, when the originating station issues a communication request, the number of times the communication is not permitted is read from the confirmation count database, and the number of times the permission is denied exceeds a predetermined number. Reading subscriber information corresponding to the identification information notified by the calling terminal from a subscriber database, notifying the mobile communication terminal corresponding to the read subscriber information, and an identification unique to the notified mobile communication terminal. The information is changed. Further, in the invention according to claim 6, in the method for preventing unauthorized use of identification information according to any one of claims 4 and 5, the switching center transmits the identification information from the originating terminal to the destination base station. When a communication request is issued, the transmission terminal moves from the communication range of the final base station to the communication range of the destination base station only when the identification information unique to the transmission terminal is present in the identification information database. It is characterized in that it is confirmed whether or not the required time exceeds the individual shortest travel time. According to a seventh aspect of the present invention, in the method for preventing unauthorized use of identification information according to any one of the fourth to sixth aspects, the plurality of exchanges are connected to the public communication network. In a service area specific to each of the one or more mobile communication carriers, a part of a predetermined communication range of each of the plurality of mobile communication carriers is installed in an overlapping positional relationship with the exchanges adjacent to each other, and The mobile communication terminal may change a communication partner to the base station having the predetermined communication range in which the communication state is the best as the mobile station moves. Further, in the invention according to claim 8, an exchange connected to a public communication network, a plurality of base stations connected to the exchange and each having a predetermined communication range,
The mobile station includes a plurality of mobile communication terminals each of which is assigned a unique identification information in advance and can be connected to the public communication network via any one of the plurality of base stations, and wherein the switching center includes the plurality of mobile stations. A transportation database storing all of the transportation available between the communication ranges of each base station and the shortest travel time, and information on the last base station that is the last communication partner for each of the plurality of mobile communication terminals And a communication history database for storing a communication end time. According to the ninth aspect of the present invention, in the mobile communication network according to the eighth aspect, the switching center transmits a signal from the transmitting terminal, which is one of the plurality of mobile communication terminals, to the plurality of base stations. When a communication request is issued to any of the called base stations,
The information of the final base station and the communication end time are read from the communication history database for the transmitting terminal, and the individual shortest travel time from the final base station to the receiving base station is read from the transportation database, and the transmitting terminal Permits communication between the calling terminal and the called base station only when the time required to move from the communication range of the final base station to the communication range of the called base station exceeds the individual shortest moving time. It is characterized by doing. In the mobile communication network according to the ninth aspect of the present invention, in the mobile communication network according to the ninth aspect, the switching center may be any one of the plurality of base stations for each of the plurality of mobile communication terminals. A number-of-confirmations database that stores the number of times the communication was rejected when a communication request was made to the subscriber, and a subscriber that stores each piece of subscriber information corresponding to identification information unique to each of the plurality of mobile communication terminals And a database. Further, in the invention according to claim 11, in the mobile communication network according to claim 10, the switching center performs the communication when the communication request is issued from the calling terminal to the called base station. When the communication is not permitted, the number of times that the communication is rejected when the transmitting station issues a communication request is read from the number-of-confirmations database, and the number of times that the rejection is exceeded exceeds a predetermined number. Reads the subscriber information corresponding to the identification information notified by the calling terminal from the subscriber database, notifies the mobile communication terminal corresponding to the read subscriber information and notifies the mobile communication terminal specific to the notified mobile communication terminal. It is characterized in that the identification information is changed. In the invention according to claim 12, in the mobile communication network according to any one of claims 9 to 11, the switching center is connected via any of the plurality of base stations. A plurality of mobile communication terminals that can be connected to the public communication network, each having an identification information database that stores unique identification information previously assigned to each of the mobile communication terminals. When a communication request is issued, only when the identification information unique to the transmitting terminal is present in the identification information database, the transmitting terminal transmits from the communication range of the final base station to the communication range of the receiving base station. It is characterized by confirming whether or not the time required for the movement exceeds the individual shortest movement time. According to a thirteenth aspect of the present invention, in the mobile communication network according to any one of the eighth to twelfth aspects, the plurality of exchanges are connected to the public communication network. A plurality of mobile communication terminals, wherein at least one of a plurality of mobile communication terminals is installed in a service area unique to each of the plurality of mobile communication carriers, and a part of a predetermined communication range of each of the plurality of mobile communication terminals is installed in an overlapping positional relationship with the exchanges adjacent to each other; Is characterized by changing a communication partner to the base station having the predetermined communication range in which the communication state is the best as the mobile station moves.

[0010] The present invention relates to a base station for a terminal device such as a mobile phone which is illegally obtained by illegally obtaining identification information of the terminal device and copying the information to another terminal device for use. If it is detected that the mobile telephone terminal used by the station requests communication with another base station within a predetermined time, it is determined that there is a possibility of unauthorized use, and this situation is repeated several times. If so, it is determined that the terminal has been used illegally, and the terminal used illegally cannot be used.

[0011] The term "within the predetermined time period" means the fastest moving means available from the previously requested base station to the next requested base station. This is the time required when using. That is, by detecting that a mobile telephone terminal having the same identification information is used from a plurality of places that cannot be moved to each other,
Can detect fraud.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Embodiments The present invention will be described below with reference to the drawings. FIG.
1 is a block diagram showing a schematic configuration of a mobile communication network according to one embodiment of the present invention. As shown in the figure, the configuration of the current communication network includes an exchange 11 connected to a public telephone network (not shown), and a base station 12 and a base station 13 (other base stations) connected to the exchange 11. The base station is not shown).

The communication area of the base station 12 (not shown)
There is a regular mobile phone 14 that can physically move within the dashed-dotted line frame, and an unauthorized mobile phone 15 (other mobile phones are not shown) in the communication area (not shown) of the base station 13. I have.

Although not shown, exchange 11 shown in the present embodiment has an identification information database storing identification information individually assigned to each of a plurality of mobile telephone terminals and information on each of a plurality of subscribers. , A transportation database that stores the transportation available between the communication areas of each base station and the shortest time when moving by using this transportation, and the last one for each mobile telephone terminal. The communication history database stores information on the base station of the communication partner and the communication end time, and a confirmation count database described later.

FIG. 2 is a flowchart showing an example of the flow of processing in this embodiment. The processing shown here is performed by a mobile telephone terminal having the same identification information as another authorized mobile telephone 14 within another predetermined time after the authorized mobile telephone 14 completes communication via the base station 12. This shows a case where a communication request has been made. In the present embodiment, it is assumed that a communication request has been made from the unauthorized mobile telephone 15 to the base station 13.

When there is a communication request from the unauthorized mobile telephone 15 to the base station 13 (Step St1), the exchange 11 searches the identification information database and finds the mobile telephone terminal (illegal mobile telephone 15) that has requested the communication. Check whether the identification information is registered as a legitimate one (Step St)
2). Here, if the identification information of the mobile telephone terminal that has made the communication request is not registered in the identification information database, the processing is terminated as communication is not permitted.

Next, the exchange 11 searches the subscriber database and confirms whether the subscriber who has requested the communication is registered as an authorized subscriber (Step St3). If the subscriber who has made the communication request is not registered in the subscriber database, the communication is not permitted and the process ends.

Next, the exchange 11 searches the communication history database for the last communication partner base station (ie, the base station 12 in this case) of the mobile telephone terminal that has made the communication request and the communication end time, and finds the means of transportation. From the database, a search is made for the shortest time required for movement from the last communication partner base station to the base station that has requested communication (step St4).

Thereafter, based on the retrieved shortest moving time, the communication end time, and the current time, the exchange 11 determines the time of the base station 12 by the time from the end of the communication to the time when the mobile telephone terminal requests the communication again. It is checked whether it is possible to move from the communication area to the communication area of the base station 13 (Step St)
5).

Here, if the unauthorized mobile telephone 15 is located at a completely distant place and is trying to communicate between the base station 12 and the base station 13 from a physically immovable place, the same It can be seen that there is another mobile communication terminal having identification information. In this embodiment, the mobile phone terminal having the same identification information is detected thereby to prevent unauthorized use. That is, if it is determined in step St5 that the mobile terminal is movable, communication is started as communication permission.

On the other hand, if it is determined that the mobile station cannot be moved, the exchange 11 searches the number-of-confirmations n for the identification information from the number-of-confirmations database (step St6). The number of confirmations n is the number of times the mobile telephone terminal corresponding to each piece of identification information has been confirmed as to whether or not the mobile telephone terminal can move as shown in step St5, and is added each time confirmation processing is performed.

In this way, the exchange 11 judges whether or not the number of confirmations n searched for has reached 3 (step St).
7) If the number has not reached 3, 1 is added to n, and the processing is terminated as communication is not permitted.

On the other hand, if the searched number of confirmations n has reached 3, the regular subscriber (ie, the user of the regular mobile telephone 14) is notified that there is a possibility that it has been used illegally.

In this case, the identification information of the legitimate mobile telephone 14 is changed, and other measures such as deleting identification information that may have been used illegally from the identification information database are taken. Therefore, thereafter, the unauthorized mobile telephone 15 whose identification information has been illegally copied cannot be used.

The identification information database, the subscriber database, the transportation database, the communication history database, the number of confirmations database, and the like described in the above embodiment are provided in the exchange for other databases or for other purposes. It is only necessary to secure a new area for each database in each storage device, so that it is possible to realize the present invention without adding a new storage device in addition to the conventional configuration. The same applies to a processing program for monitoring and preventing the above-mentioned unauthorized use.

Further, in the above-described embodiment, the switching center 11 is connected to a public line network, and another switching center or another mobile communication carrier can be connected to the public line network. Therefore, as in the above-described embodiment, the switching center of another mobile communication carrier or the like is provided with an identification information database, a subscriber database, a transportation database, a communication history database, a check count database, and the like. It is possible to prevent unauthorized use of the telephone terminal across a plurality of mobile communication carriers.

Further, the present invention is not limited to a mobile telephone communication network, but may be applied to a mobile communication network that covers a wide service area by a plurality of cellular (small zones) or micro cells. Symbols and images may be exchanged.

B. Application Examples Although the above is an example in which the present invention is applied to a communication network such as a mobile phone, there are other application examples in which the present invention has unique effects. For example, unauthorized use of personal identification information written on a cash card, a credit card, or the like can be prevented. Hereinafter, this will be briefly described.

ATM (Automatic Teller Machine: automatic transaction device) installed in a branch office or a store of a financial institution or the like.
It is possible to withdraw cash and transfer / transfer money using a device such as a cash dispenser or a CD (Cash Dispenser). At this time, personal identification information necessary for identifying the user is written in a cash card, a credit card, or the like (hereinafter, simply referred to as a card as necessary).

Therefore, a user database (corresponding to a subscriber database) for storing information on each of a plurality of users (contractors) in a host computer or the like of the head office, and a transaction account or card issued to each user. An identification information database for storing identification information, a transportation system usable between devices such as ATMs and CDs, a transportation database for storing the shortest time when traveling by using this transportation system, A usage history database (corresponding to a communication history database) for storing information on a used device and a use operation end time, and a confirmation count database are provided.

Each device such as an ATM and a CD is connected to a host computer by a communication line.
The shortest time required to move between places where devices such as TMs and CDs are installed can be assumed in advance from available transportation means.

Therefore, when a person other than a legitimate user (contractor) who owns a card such as a cash card illegally obtains the identification information of the card and copies the information to another card for use, If it is detected that a card used in a certain device such as an ATM or a CD is going to be used in another device within a predetermined time, it is determined that the card may have been used illegally. If it is repeated several times, it is determined that the card has been used illegally, and the card used illegally cannot be used.

It is needless to say that, within the predetermined time, the fastest transportation available from the previously used device to the device for which the user has been confirmed is used. It is the time required for the case. That is, by detecting that cards having the same identification information are used from a plurality of devices such as ATMs and CDs which cannot be moved with each other, fraud can be found. In particular, cash cards and the like can be used in Japan and overseas, but this method is effective not only in Japan but also in a wide area such as overseas.

[0034]

As described above, according to the present invention, unique transaction information is assigned to each of the devices in advance, and various transaction operations are performed through any of a plurality of terminal devices connected to the host computer. When a user confirmation request is issued from any of the plurality of user identification means to be obtained, information on the last used terminal device and the use end time are read from the usage history database for the user identification means, and the last used terminal is used. The shortest travel time from the device to the terminal device to which the user confirmation request was issued is read from the transportation means database, and the user identification means is used to move from the terminal device last used to the terminal device to which the user confirmation request was issued. Only when the required time exceeds the shortest traveling time, various transaction operations by the user identification means are permitted. In addition, when various transaction operations related to the user confirmation request are not permitted, the number of times the user confirmation request issued by the user identification means has been rejected is read from the confirmation count database, and the rejection is made. If the number of times exceeds a predetermined number, the user information corresponding to the unique identification information notified by the user identification means is read from the user database, and is read to the user identification means corresponding to the read user information. Change unique identification information. In addition, when a user confirmation request is issued from the user identification unit, the user identification unit transmits the user confirmation request from the terminal device last used only when identification information unique to the user identification unit exists in the identification information database. Confirms whether the time required to move to the terminal device where the request was issued exceeds the shortest travel time, so there is no need to add a large-scale device, etc., and effectively use a credit card, mobile communication terminal, etc. An effect is obtained that a method for preventing unauthorized use of identification information and a mobile communication network that can monitor and prevent unauthorized use of a mobile communication network can be realized.

By checking not only the identification information of the mobile telephone terminal but also the travel time between base stations, the efficiency of preventing unauthorized use can be improved. This will become even more effective as the coverage area expands from one country to the world. Since mobile phones are becoming available on a global scale, confirming the travel time for the same identification information will prevent fraudulent use not only in the domestic area but also in a wide overseas area. Further, the present invention can be dealt with by adding a function on the switching center side without adding a function on the terminal device side.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a mobile communication network according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of a processing flow according to the embodiment.

[Explanation of symbols]

 11 switching station 12 base station (final base station) 13 base station (terminating base station) 14 regular mobile phone (mobile communication terminal) 15 unauthorized mobile phone (calling terminal)

Claims (13)

(57) [Claims] A unique identification information is assigned to each of them in advance and used from any of a plurality of user identification means capable of performing various transaction operations via any of a plurality of terminal devices connected to a host computer. When a user confirmation request is issued, the information of the last used terminal device and the use end time are read from the use history database with respect to the user identification means, and the user confirmation request is issued from the last used terminal device. The shortest travel time to the terminal device is read from the transportation database, the time required for the user identification means to travel from the last used terminal device to the terminal device for which the user confirmation request was issued is The identification information is characterized by permitting the various transaction operations by the user identification means only when the shortest travel time is exceeded. Positive use prevention method. 2. The number of times that the user confirmation request issued by the user identification means has been rejected when the various transaction operations related to the user confirmation request have been rejected. When the number of times of rejection exceeds a predetermined number, the user information corresponding to the unique identification information notified by the user identification means is read from a user database, and the read user is read. 2. The method according to claim 1, wherein the identification information unique to the user identification means corresponding to the information is changed. 3. When a user confirmation request is issued from the user identification means, the user identification means is used last only when identification information unique to the user identification means exists in an identification information database. And confirming whether or not the time required for the movement from the terminal device to the terminal device to which the user confirmation request has been issued exceeds the shortest movement time. For preventing unauthorized use of the identification information described in. 4. An exchange (1) connected to a public communication network.
1) is a call originating from any one of a plurality of mobile communication terminals (14) which are previously assigned unique identification information and can be connected to the public communication network via any one of a plurality of base stations. When a communication request is issued from the terminal (15) to the destination base station (13) which is one of the plurality of base stations connected to the exchange and each having a predetermined communication range, The information of the last base station (12), which is the last communication partner, and the communication end time are read from the communication history database, the shortest travel time from the last base station to the called base station is read from the transportation database, Only when the time required to move from the communication range of the final base station to the communication range of the terminating base station exceeds the shortest travel time, A method for preventing unauthorized use of identification information, wherein communication between a calling terminal and the called base station is permitted. 5. The communication system according to claim 1, wherein when the communication is not permitted when the calling terminal issues a communication request to the called base station, the communication is disabled when the calling station issues the communication request. The number of times of permission is read from the number of confirmations database, and when the number of times of non-permission exceeds a predetermined number, subscriber information corresponding to the identification information notified by the calling terminal is read from the subscriber database. 5. The method according to claim 4, further comprising: notifying a mobile communication terminal corresponding to the read subscriber information, and changing identification information unique to the notified mobile communication terminal. . 6. The switching center, when a communication request is issued from the originating terminal to the destination base station, the originating terminal transmits the originating terminal only when identification information unique to the originating terminal exists in an identification information database. 6. The system according to claim 4, wherein it is determined whether or not the time required to move from the communication range of the last base station to the communication range of the called base station exceeds the individual shortest movement time. A method for preventing unauthorized use of the identification information described in any of the above. 7. A plurality of exchanges, each having one or more mobile communication carriers connected to the public communication network, each having a predetermined service area between exchanges adjacent to each other within a service area specific to each of the mobile communication carriers. The plurality of mobile communication terminals are installed in a positional relationship in which a part of the communication range overlaps, and the plurality of mobile communication terminals change a communication partner to the base station having the predetermined communication range in which the communication state is the best as the mobile terminal moves. 7. The method according to claim 4, wherein the identification information is illegally used. 8. An exchange connected to a public communication network, a plurality of base stations connected to the exchange and each having a predetermined communication range, each of which is assigned unique identification information in advance, and A plurality of mobile communication terminals that can be connected to the public communication network via any one of the plurality of base stations, wherein the exchange uses the communication range of each of the plurality of base stations. A transportation database that stores all possible transportations and the shortest travel time; and a communication history database that stores information on the last base station that is the last communication partner for each of the plurality of mobile communication terminals and communication end time. A mobile communication network, comprising: 9. The switching center, when a communication request is issued from a transmitting terminal that is one of the plurality of mobile communication terminals to a receiving base station that is one of the plurality of base stations, Reading the information of the last base station and the communication end time from the communication history database; reading the individual shortest travel time from the last base station to the destination base station from the transportation database; The communication between the calling terminal and the called base station is permitted only when the time required to move from the communication range of the called base station to the communication range of the called base station exceeds the individual shortest moving time. The mobile communication network according to claim 8, wherein 10. The number of confirmations for storing the number of times that the exchange is rejected when a communication request is made to any one of the plurality of base stations with respect to each of the plurality of mobile communication terminals. The mobile communication network according to claim 9, further comprising: a database; and a subscriber database storing subscriber information corresponding to identification information unique to each of the plurality of mobile communication terminals. 11. The switching center issues a communication request from the confirmation count database when the communication is rejected when a communication request is issued from the calling terminal to the called base station. In this case, the number of times communication has been rejected is read out. If the number of times rejection exceeds a predetermined number, the subscriber corresponding to the identification information notified by the calling terminal from the subscriber database is read. The mobile communication network according to claim 10, wherein the mobile communication network reads information, notifies the mobile communication terminal corresponding to the read subscriber information, and changes identification information unique to the notified mobile communication terminal. 12. The switching center stores each unique identification information assigned in advance to each of a plurality of mobile communication terminals that can be connected to the public communication network via any of the plurality of base stations. The switching center has an identification information database, and when a communication request is issued from the originating terminal to the destination base station, the exchange only performs when the identification information unique to the originating terminal exists in the identification information database. 10. The system according to claim 9, wherein the originating terminal checks whether the time required for moving from the communication range of the final base station to the communication range of the destination base station exceeds the individual minimum travel time. A mobile communication network according to any one of claims 11 to 11. 13. A plurality of exchanges, each having one or more mobile communication carriers connected to the public communication network, having a predetermined service area between the exchanges adjacent to each other within a service area specific to each of the mobile communication carriers. The plurality of mobile communication terminals are installed in a positional relationship in which a part of the communication range overlaps, and the plurality of mobile communication terminals change a communication partner to the base station having the predetermined communication range in which the communication state is the best as the mobile terminal moves. The mobile communication network according to any one of claims 8 to 12, wherein: