JPH09322251A - Mobile communication system and illegal use detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect illegal use in an early stage with respect to the mobile communication system and illegal use detection method detecting an illegal use by a clone terminal equipment. SOLUTION: In this mobile communication system, a plurality of exchange stations 2 arranged distributingly are connected to a home exchange station 1 and communication is made to a mobile terminal equipment 3 in a service area 4 of the exchange station 2. In this case, together with position information corresponding to a mobile terminal equipment, information of at least any of a final calling telephone number, or a final caller telephone number or a final position registration date and time and final position information is stored in a subscriber data memory 6 of the home exchange station 1, and in the case of position registration or dialing, the information stored in the subscriber data memory 6 is collated with information stored in a memory 11 of the mobile terminal equipment 3 and presence of a clone terminal equipment is discriminated when the collation indicates dissidence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system such as a car phone or a mobile phone and a method for detecting unauthorized use. In a mobile communication system using mobile terminals such as car phones and mobile phones, each mobile terminal has a serial number, an authentication key based on a random number, etc. in addition to the assigned telephone number. Using this authentication key, authentication processing is performed at the start of communication as to whether or not the mobile terminal has a formal contract. In this case, by using a clone terminal with the same phone number and authentication key of the officially contracted mobile terminal, there is a problem of illegal use of impersonating the officially contracted mobile terminal for communication. In addition, it is demanded to detect it with certainty.

[0002]

2. Description of the Related Art In a mobile communication system, a manufacturing number, a personal identification number, etc. of a mobile terminal are registered on the exchange side, and when the communication is started, the mobile terminal automatically sends out the production number, the personal identification number, etc. On the exchange side, the manufacturing number and the secret code from the mobile terminal are collated with the registered manufacturing number and the secret code, and if the collation coincides, communication is started as a formal contracted mobile terminal.

[0003] However, since the manufacturing number, the personal identification number, etc. transmitted from the mobile terminal are transmitted by radio frequency, they can be intercepted. By intercepting the manufacturing number, the personal identification number, etc., the manufacturing number, the personal identification number, etc. There is a problem of creating a clone terminal that sends out a number and illegally using it.

In order to solve such a problem of unauthorized use, the count value of the number of outgoing calls at the mobile terminal and the count value of the outgoing call count corresponding to the mobile terminal at the exchange side are
A method is known in which, when a mobile terminal originates a call, the exchange side makes a comparison, and when there is a mismatch, it is determined that a clone terminal exists. Further, the moving speed of the mobile terminal is calculated based on the position information and time information at the time of the previous call connection request of the mobile terminal, and the position information and time information at the time of the current call connection request. If the speed exceeds the maximum value, a method of determining that there is a clone terminal has been proposed (see, for example, JP-A-7-46661).

Various methods have been proposed in which the authentication process is complicated to make it difficult for an unauthorized user to impersonate a mobile terminal with an official contract even if intercepted by an unauthorized user. For example, a plurality of authentication keys are encrypted and transmitted / received. Then, it decrypts and verifies the authentication key, updates some authentication keys for each communication with random numbers, etc., and estimates the encrypted authentication key at the next communication start even by intercepting the encrypted authentication key. Has been proposed (see, for example, JP-A-7-162954).

[0006]

Unauthorized use by a clone terminal causes a charge to a mobile terminal with a formal contract. In the conventional example, when an unauthorized use by a clone terminal is detected, this mobile terminal will be charged. A method of avoiding an increase in damage by denying communication by means of the communication is considered. In this case, the detection of unauthorized use by the clone terminal is performed only when the mobile terminal makes a call in the conventional example. Therefore, there is a problem that the damage increases when the transmission interval is long.

Further, as information for detecting unauthorized use, as described above, there is a problem that fixed information such as a manufacturing number and a personal identification number can be easily copied by interception.
Also, changing information such as the number of times of communication and the previous position information cannot be copied immediately by interception, but since there is a high possibility that the change algorithm is estimated, there is a problem that unauthorized use cannot be reliably detected. is there. In addition, a method of calculating the moving speed of the mobile terminal using the previous position information and time information, and the current position information and time information, and determining whether or not the moving speed is a common sense is an aircraft, Since it is difficult to distinguish a high-speed moving body such as an automobile running on a high-speed railway or a highway from a normal moving body, there is a problem that it is not practical in view of current traffic conditions.

[0008] Further, in the method of performing the update process while using a plurality of secret code keys described above, it is difficult to estimate the encrypted secret code key next time even if the encrypted secret code key is intercepted. However, there is a problem that the processing is complicated and a high-speed processing configuration is required, resulting in an increase in cost. It is an object of the present invention to economically detect the presence of a clone terminal even when registering the location of a mobile terminal.

[0009]

A mobile communication system of the present invention will be described with reference to FIG. 1. (1) A plurality of distributed exchanges 2 are connected to a home exchange 1 and the exchanges are connected to each other. In the mobile communication system including the mobile terminal 3 that communicates within the service area 4 of 2, the home switching center 1
Is subscriber data that stores position information of the mobile terminal 3 corresponding to the switching center 2 and also stores at least one of the last calling telephone number of the mobile terminal 3, the last calling telephone number, and the last location registration date and time. Exchange 6 with memory 6
Alternatively, the mobile terminal 3 has a configuration for determining the presence / absence of a clone terminal based on the information stored in the subscriber data memory 6 of the home switching center 1 when the position of the mobile terminal 3 is registered or when the mobile terminal 3 makes a call. Since the presence / absence of the clone terminal can be determined even at the time of registering the position of the mobile terminal 3, it is possible to detect unauthorized use at an early stage.

(2) The mobile terminal 3 is provided with a memory 11 for accumulating at least one of the information of the last calling telephone number, the last calling telephone number and the last location registration date and time. Information stored in the memory 11 of the mobile terminal 3 at the time of location registration or call origination and the home exchange 1
The information stored in the subscriber data memory 6 of
It is possible to provide a configuration in which a clone terminal is detected by collation mismatch.

(3) The exchange 2 receives the final position registration date and time and the final position information stored in the subscriber data memory 6 of the home exchange 1 when the position of the mobile terminal 3 is registered or transmitted. The mobile terminal 3 has a configuration for transmitting the final position registration date and time and the final position information from the exchange 2, and the mobile terminal 3 is controlled by the control unit 10 to obtain the final position registration date and time and the final position. And a display section for displaying
The presence / absence of a clone terminal is determined based on the final position registration date and time and the final position displayed on the display unit.

(4) In the unauthorized use detection method of the present invention, the home exchange 1 having the subscriber data memory 6 for managing the information such as the position of the mobile terminal 3 and the exchange connected to the home exchange 1. Station 2 and service area 4 of this exchange 2
In a method of detecting unauthorized use in a mobile communication system including a mobile terminal 3 which communicates within the mobile terminal 3, the subscriber data memory 6 of the home switching center 1 is provided with a final calling telephone number or a final calling number of the mobile terminal 3. Information of at least one of the person's telephone number and the last location registration date and time is stored in the subscriber data memory 6 at the mobile terminal 3 or the switching center 2 at the time of location registration or transmission of the mobile terminal 3. It includes a process of determining the presence / absence of a clone terminal based on the stored information and the stored information.

(5) The mobile terminal 3 stores the telephone number when making a call in the memory 11, and the exchange 2 transfers the telephone number when making a call to the home exchange 1 and overwrites it in the subscriber data memory 6. The final calling telephone number stored in the memory 11 of the mobile terminal 3 is collated at the time of registering the location of the mobile terminal 3 or at the time of calling, and when there is a mismatch, it is determined that there is a clone terminal. In addition, a process of performing an unauthorized use display process may be included.

(6) The exchange 2 notifies the mobile terminal 3 of the caller telephone number when the mobile terminal 3 receives a call, and
The final caller stored in the memory 11 of the mobile terminal 3 is transferred to the home switching center 1 and overwritten in the subscriber data memory 6 to be stored as a final caller telephone number. Include a process of collating the telephone number with the last caller telephone number stored in the subscriber data memory 6 of the home switching center 1, determining that there is a clone terminal when the collation does not match, and performing illegal use display processing. You can

(7) When registering the position of the mobile terminal 3, the home switching center 1 overwrites the position information of the mobile terminal with the position registration date and time in the subscriber data memory 6 and stores it as the final position registration date and time and the final position information. Then, the mobile switching center reads out the final location registration date and time and the final location information stored in the subscriber data memory of the home switching center and transmits them to the mobile terminal 3 when the mobile terminal location is registered or transmitted. , The last location registration date and time and the last location information are extracted and displayed on the display unit,
A process of determining the presence / absence of a clone terminal can be included based on the display content of the display unit and the stored previous position registration date and time and position.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a main part of a first embodiment of the present invention, in which 1 is a home switching center, 2 is a switching center,
Reference numeral 3 indicates a mobile terminal, and 4 indicates a service area. Further, 5 is a management control unit, 6 is a subscriber data memory, 7 is a transmission / reception unit, 8 is a control processing unit, 9 is a transmission / reception unit, 10 is a control unit, and 11 is a memory. The exchanges 2 are distributed and connected to the home exchange 1, so that the mobile terminals 3 can communicate within the service area 4 of each exchange 2. Also the transmitter / receiver 7
It is also possible to disperse and arrange the wireless transmission / reception function as a base station.

The subscriber data memory 6 of the home switching center 1
Is to register an authentication key and location information corresponding to the mobile terminal, as in the conventional example, and whether the mobile terminal is an officially contracted mobile terminal is authenticated by the authentication key and the like, and based on the location information A call is made in the case of an incoming call to the mobile terminal 3. Further, in the embodiment of the present invention, the final calling telephone number or the final calling telephone number is further stored corresponding to the mobile terminal.

The mobile terminal 3 is also provided with a memory 11 for storing the telephone number of the other party when making a call or the telephone number of the other party when receiving a call. The memory 11 can also use a partial area of the memory for speed dial, redial, telephone directory, and the like. Further, it has a dial button (not shown) and a transmission / reception function. Further, as indicated by a dotted arrow, when moving between the service areas 4 or when the power is turned on, the location registration request of the mobile terminal 3 is issued by the control unit 10 by the control of the control unit 10.
Sent to

Further, the exchange 2 has a transmitting / receiving section 7 and a control processing section 8
The mobile terminal 3 is connected to the home switching center 1 and allows the mobile terminal 3 in the service area 4 to communicate. When the mobile terminal 3 makes a position registration request or makes a call, the mobile terminal 3
Authenticates whether the mobile terminal is an official contract mobile terminal,
When the authentication is OK, the location registration is performed in the subscriber data memory 6 of the home exchange 1. When the home switching center 1 only manages the location of the mobile terminal 3, etc., it sends and receives a call request and an incoming call request including a telephone number to and from the mobile communication switching center which performs a switching connection process. Control processing unit 8
It is performed by the control of.

FIG. 2 is a sequence explanatory diagram of the first embodiment of the present invention, which will be described with reference to FIG. In a mobile communication system including a mobile terminal 3, a switching center 2 and a home switching center 1, when the mobile terminal 3 makes a call and dials the telephone number a of the other party, the control section 10 controls the transmission / reception section 9 This telephone number a is transmitted to the exchange 2 via the telephone and stored in the memory 11. The storage in the memory 11 can be performed by the same control as the redial function, for example. Further, by overwriting, it can be stored as the final calling telephone number.

The exchange 2 transfers the telephone number a from the mobile terminal 3 received by the transmitter / receiver 7 to the home exchange 1 in the control processor 8. The subscriber data memory 6 of the home exchange 1 has a structure for storing the final calling telephone number a ′ together with the position information (not shown in FIG. 2), the authentication type, the authentication key, etc. corresponding to the subscriber number. Then, the calling telephone number transferred from the exchange 2 is stored in the area of the subscriber number corresponding to the mobile terminal 3 on the calling side as the final calling telephone number by overwriting, for example, under the control of the management control unit 5. If the home switching center 1 has the function of a mobile communication switching center, it analyzes the transferred telephone number and sends a calling request including the calling telephone number to the switching center in which the other subscriber is accommodated. It will be.

A position registration request is automatically sent from the mobile terminal 3 when the mobile terminal 3 moves to another service area during or after a call, or when the power is turned off and then turned on. To be done. The exchange 2 requests the subscriber data from the home exchange 1 by this location registration request. As a result, the final calling telephone number a ′ is read from the subscriber data memory 6 together with the authentication type and the authentication key corresponding to the subscriber number of the mobile terminal of the location registration request, and sent to the exchange 2.

The exchange 2 is controlled by the control processor 8
The authentication processing data formed based on the authentication type and the authentication key is transmitted to the mobile terminal 3. The mobile terminal 3 performs authentication calculation processing by the control unit 10, transmits the calculation result to the exchange 2, and at the same time, sends the final calling telephone number a stored in the memory 11.
Send Note that various known methods can be applied to the authentication process for the mobile terminal 3.

When the exchange 2 recognizes that the mobile terminal has a formal contract by the authentication process, the final call telephone number a'from the subscriber data memory 6 of the home exchange 1 and the final call from the memory 11 of the mobile terminal 3 are sent. The control processing unit 8 collates the telephone number a. If there is no clone terminal, mobile terminal 3
The final outgoing call telephone number stored in the memory 11 of the home exchange station 1 is the same as the final outgoing call telephone number stored in the subscriber data memory 6 of the home exchange 1. That is, collation match (a = a ')
Therefore, it is determined that there is no clone terminal, and the location registration process is performed.

If there is an illegal use by the clone terminal,
The final calling telephone number stored in the memory 11 of the formal contracted mobile terminal 3 and the subscriber data memory 6 of the home exchange 1
The probability that the last outgoing telephone number stored in is the same is 0
Therefore, when collation is performed, collation disagreement (a ≠ a ′) occurs. In this case, it is determined that there is a clone terminal and the maintenance person is notified. For example, it outputs a message, sounds an alarm, and notifies the mobile terminal 3 of a clone terminal detection.

In response to the clone terminal detection notification, the mobile terminal 3 displays the presence of the clone terminal by detecting and displaying the clone terminal, outputting an alarm sound, blinking the lamp, and the like. As a result, it is possible to notify the telecommunications carrier of the detection of the clone terminal and take countermeasures against unauthorized use by the clone terminal.
In addition, when it is determined that there is a clone terminal as described above during unauthorized use using a clone terminal, the clone terminal detection is also notified to this clone terminal, and the unauthorized use is detected on the exchange side. Can be recognized. In addition, the maintenance person can take measures to reject communication by this mobile terminal so that damage caused by unauthorized use will not increase.

When the mobile terminal makes a call, the mobile terminal is authenticated. At that time, the final outgoing telephone number stored in the memory 11 of the mobile terminal 3 is stored.
The final calling telephone number stored in the subscriber data memory 6 of the home exchange 1 is checked to determine whether or not there is a clone terminal. Further, even when the service area 4 is moved during a call, the location registration process is performed, so that the presence or absence of the clone terminal can be determined as described above.

FIG. 3 is a sequence explanatory diagram of the second embodiment of the present invention. In the mobile communication system including the home exchange 1, the exchange 2 and the mobile terminal 3, the incoming call to the mobile terminal 3 is received. At the same time, a call is made from the exchange 2 and the caller telephone number c is transmitted. The mobile terminal 3 stores the caller telephone number c in the memory 11. In this case also, by overwriting, it is stored in the memory 11 as the last caller telephone number.

The exchange 2 transfers the caller's telephone number to the home exchange 1, and under the control of the management controller 5 of the home exchange 1, the subscriber data memory 6 stores the subscriber number area corresponding to the mobile terminal. Can be overwritten and stored as the last caller phone number. Then, when the mobile terminal 3 answers the call, the mobile terminal 3 enters the call state, and the line is disconnected when the call ends.

When the mobile terminal 3 moves between the service areas 4, or when the power is turned on after the power is turned off, the location registration request is automatically issued from the mobile terminal 3 by the exchange 2.
Sent to When the exchange 2 requests the home exchange 1 for the subscriber data of the mobile terminal 3 of the location registration request, the management control unit 5 of the home exchange 1 reads from the subscriber data memory 6 the authentication type, the authentication key, and the final Caller's phone number c '
Is read out and transferred to the exchange 2.

Authentication processing is performed between the exchange 2 and the mobile terminal 3 as described above, and the mobile terminal 3 sends to the exchange 2 the final caller telephone number c stored in the memory 11 together with the authentication calculation processing result. Send. The exchange 2 in the control processing unit 8 has the final caller telephone number c stored in the memory 11 of the mobile terminal 3 and the last caller telephone number stored in the subscriber data memory 6 of the home exchange 1. Match with c '.

If there is no clone terminal, c =
It should be c ′. Therefore, if there is a matching match, it is determined that there is no clone terminal, and location registration processing is performed. If there is a clone terminal, the probability that the caller telephone number stored in the memory 11 of the mobile terminal 3 and the caller telephone number stored in the subscriber data memory 6 are different with respect to the telephone number of the previous caller. Is a very large value, resulting in collation mismatch (c ≠ c ′). In that case, it is determined that there is a clone terminal, and the maintenance person is notified by outputting a message or sounding an alarm, and the mobile terminal 3 is notified of the clone terminal detection.

With this clone terminal detection notification, as in the case of the clone terminal detection by collating the last outgoing telephone number, the mobile terminal 3 has the clone terminal by detecting and displaying the clone terminal, outputting an alarm sound, blinking the lamp, and the like. Is displayed. Also, even when the clone terminal is used illegally, the clone terminal is notified that there is a clone terminal,
The exchange side can recognize that the unauthorized use has been detected. In addition, the maintenance person can take measures to reject communication by this mobile terminal so that damage caused by unauthorized use will not increase.

Also, when the mobile terminal 3 makes a call, the authentication process is performed. At that time, the final caller telephone number stored in the memory 11 of the mobile terminal 3 and the home exchange 1 join. The presence or absence of the clone terminal can be determined by collating with the final caller telephone number stored in the person data memory 6. Further, even when the service area 4 is moved during a call, the location registration process is performed, so that the presence or absence of the clone terminal can be determined as described above.

FIG. 4 is an explanatory view of the essential parts of the third embodiment of the present invention, in which the same reference numerals as those in FIG. 1 indicate the same parts, and 12 is a display part. The display unit 12 of the mobile terminal 3 is the same as the display unit such as a liquid crystal panel provided in the general mobile terminal 3, and the control unit 10 sends it under the control of the control processing unit 8 of the exchange 2. It has a function of extracting the position registration date and time and the position information and displaying them on the display unit 12. Further, the subscriber data memory 1 of the home exchange 1 has an area for accumulating location registration date and time and location information corresponding to the subscriber number of the mobile terminal.

When the power of the mobile terminal 3 is turned on or when the mobile terminal 3 moves between the service areas 4, the exchange 2 performs an authentication process by making a location registration request, and in the case of authentication OK, the subscriber of the home exchange 1 The final position registration date and time and the final position information stored in the data memory 6 are read out and transmitted to the mobile terminal 3, and the present position registration date and time and position information are stored in the subscriber data memory 6 by overwriting or the like.

As described above, the mobile terminal 3 automatically makes a location registration request by turning on the power or moving between the service areas 4, and receives the final location registration date and time and the final location information from the exchange 2. The display unit 1 is controlled by the control unit 10.
The last position registration date and time and the last position are displayed in 2. Therefore, every time the power is turned on or the service area 4 is moved, the previous position registration date and time and the position are displayed. Therefore, it is determined whether the displayed contents and the stored contents are the same. It can be determined that there is a clone terminal.

FIG. 5 is a sequence explanatory diagram of the third embodiment of the present invention. In the mobile communication system including the home switching center 1, the switching center 2 and the mobile terminal 3, the home switching center 1 joins. The person data memory 6 has a configuration for accumulating an authentication type and an authentication key corresponding to a subscriber number, a position registration date and time, and an ID of a serving exchange station as position information.

When the power of the mobile terminal 3 is turned on or when the mobile terminal 3 moves between the service areas 4, the mobile terminal 3 automatically transmits a location registration request to the exchange 2, and the exchange 2 follows the location registration request. A request for subscriber data is made to the home exchange 1, and the home exchange 1 sends the authentication type and the authentication key read from the subscriber data memory 6 to the exchange 2. The exchange 2 performs an authentication process with the mobile terminal 3 that has made the location registration request based on the subscriber data including the authentication type and the authentication key. If the authentication is OK, the exchange 2 performs home exchange. Request station 1 to set location information.

Then, the location registration date and time t stored in the subscriber data memory 6 and the location information obtained by converting the ID of the existing exchange station α into the location p by the location information conversion table are moved via the exchange station 2. The location registration date and time s of this time and the ID of the serving exchange station β are transmitted to the terminal 3 according to the location information setting request.
And overwrite. Therefore, it is stored as the final position registration date and time and the final position information.

The mobile terminal 3 receives the previous location p and the location registration date and time t and displays it on the display unit 12. As a result, the date and time of the last location registration stored and the location
If it is the same as the content displayed on the display unit 12, it can be determined that there is no clone terminal, but if it is not the same, the location registration is performed by the clone terminal between the previous location registration and the current location registration. Since this is the case, it is possible to judge that there is a clone terminal, notify the communication carrier of the detection of the clone terminal, and prevent an increase in damage.

At the time of calling, the clone terminal is also authenticated by performing the authentication processing and transmitting and displaying the final position registration date and time and the final position information stored in the subscriber data memory 6 to the calling mobile terminal. The presence or absence of can be determined. Therefore, the presence / absence of the clone terminal can be determined not only at the time of making a call but also at the time of location registration, so that the unauthorized use can be detected early.

At the time of requesting the location registration of the mobile terminal 3, the location registration date and time is also stored in the memory of the mobile terminal 2, and the final location registration date and time and the final location registration date and time stored in the subscriber data memory 6 are described above. Whether or not there is a clone terminal can be determined by collating in the same manner as in collating the last calling telephone number or the last calling telephone number.

[0044]

As described above, according to the present invention, the final calling telephone number of the telephone number of the other subscriber when the mobile terminal 3 makes a call, or the telephone number of the other subscriber when the mobile terminal 3 receives a call. The last caller's telephone number, or at least one of the last location registration date and time and the last location information,
The data is stored in the memory 11 of the mobile terminal 3 and the subscriber data memory 6 of the home switching center 1 and collated at the time of requesting location registration or at the time of call origination. , The information to be collated is not fixed information but variable information, but it does not change with a fixed algorithm, and if there are multiple pieces of information for collation, even if it is intercepted, it will be used in the next communication. It is difficult to estimate the information for collation. Therefore, it is possible to prevent the illegal use, and when the illegal use is performed, it can be detected even at the time of the position registration request, so that there is an advantage that the illegal use can be detected early.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a sequence according to the first embodiment of this invention.

FIG. 3 is an explanatory sequence diagram of the second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a main part of a third embodiment of the present invention.

FIG. 5 is a sequence explanatory diagram of the third embodiment of the present invention.

[Explanation of symbols]

 1 Home Switching Center 2 Switching Center 3 Mobile Terminal 4 Service Area 5 Management Control Unit 6 Subscriber Data Memory 7 Transmitter / Receiver Unit 8 Control Processing Unit 9 Transmitter / Receiver Unit 10 Control Unit 11 Memory

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kimio Yashiki 3-9-18 Shin-Yokohama, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Fujitsu Communication Systems Ltd. (72) Norio Yamaguchi, Shin-Yokohama, Kohoku-ku, Yokohama, Kanagawa Prefecture 9-9-18 Fujitsu Communication Systems Limited (72) Inventor Koichi Hatakami 3-9-18 Shin-Yokohama, Kohoku Ward, Yokohama City, Kanagawa Prefecture Fujitsu Communication Systems Limited

Claims (7)

[Claims] 1. A mobile communication system including a mobile terminal which connects a plurality of distributed exchanges to a home exchange and communicates within the service area of the exchange, wherein the home exchange is And a subscriber data memory for accumulating position information of the mobile terminal and accumulating at least one information of a last call telephone number, a last caller telephone number, and a last location registration date and time of the mobile terminal, the exchange The station or the mobile terminal is provided with a configuration for determining the presence or absence of a clone terminal based on the information stored in the subscriber data memory of the home exchange when the location of the mobile terminal is registered or when the mobile terminal originates a call. A characteristic mobile communication system. 2. The mobile terminal is provided with a memory for accumulating at least one information of a last calling telephone number, a last calling telephone number, and a last location registration date and time, and the switching center registers the location of the mobile terminal. At the time of calling or at the time of calling, the information stored in the memory of the mobile terminal is collated with the information stored in the subscriber data memory of the home exchange, and the clone terminal is detected by the collation mismatch. The mobile communication system according to claim 1, wherein: 3. The switching center sends the final position registration date and time and the final position information stored in the subscriber data memory of the home switching center to the mobile terminal at the time of location registration or call origination of the mobile terminal. In the mobile terminal, the mobile terminal extracts a final location registration date and time and final location information from the exchange, and a final location registration date and time and final location information controlled by the control section. The mobile communication system according to claim 1, further comprising: a display unit that displays 4. A home exchange having a subscriber data memory for managing information such as the location of a mobile terminal, an exchange connected to the home exchange, and communication within the service area of the exchange. A method of detecting unauthorized use in a mobile communication system including a mobile terminal, comprising: registering a final calling telephone number of the mobile terminal or a final calling telephone number or final location in the subscriber data memory of the home exchange. At least one piece of information of date and time is stored, and the information stored in the subscriber data memory at the mobile terminal or the switching center and the stored information are stored at the time of location registration or transmission of the mobile terminal. A method for detecting unauthorized use, comprising the step of determining the presence / absence of a clone terminal based on the above. 5. The mobile terminal stores a telephone number at the time of calling in a memory, and the switching center transfers the telephone number at the time of calling to the home switching center and overwrites it in the subscriber data memory. The final outgoing telephone number stored in the memory of the mobile terminal and the final outgoing telephone number stored in the subscriber data memory of the home switching center, which are stored as the final outgoing telephone number and stored or registered at the location of the mobile terminal. It collates with the telephone number, and if there is a mismatch, it is determined that there is a clone terminal,
The unauthorized use detection method according to claim 4, further comprising a step of performing an unauthorized use display process. 6. The switching center, when receiving an incoming call to the mobile terminal, notifies the mobile terminal of the caller's telephone number, transfers it to the home switching center, overwrites it on the subscriber data memory, and makes a final call. The last caller telephone number stored in the memory of the mobile terminal and the last caller stored in the subscriber data memory of the home switching center when the mobile terminal stores the location or makes a call. The unauthorized use detection method according to claim 4, further comprising a step of performing a display of an unauthorized use display process by checking the person's telephone number, judging that there is a clone terminal when there is a mismatch in checking. 7. The home switching center, when registering the location of the mobile terminal, overwrites the location information of the mobile terminal with the location registration date and time in the subscriber data memory and stores it as the final location registration date and time and the final location information. , The switching center reads the final position registration date and time and the final position information stored in the subscriber data memory of the home switching center at the time of the position registration or the call origination of the mobile terminal, and transmits to the mobile terminal, The mobile terminal extracts the final location registration date and time and the final location information and displays it on a display unit, and based on the display content of the display unit and the stored previous location registration date and time, the clone. The unauthorized use detection method according to claim 4, further comprising a step of determining the presence or absence of a terminal.