JPH11313377A - Mobile data communication system, mobile terminal therefor and data communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a party posing as a possessor of a terminal by sending discrimination information to discriminate new connection or re-connection to send a data communication device via a mobile station device, allowing the base station device to receive a connection request signal from a mobile communication device to discriminate the new connection or the re-connection and continuing data communication after that. SOLUTION: A gateway GW receives a connection request signal denoting re-connection from a mobile terminal PS1 and inquires of the mobile terminal connecting to a base station CS1 before the re-connection about confirmation of connection and transfers a connection state confirmation request signal to the base station CS1 before the re-connection via a connection. The base station C1 sends the connection state confirmation request signal to the mobile terminal in existence in a cell of itself via a radio channel. When no reply comes from the terminal, the (not shown) CS1 sends no acknowledgement to the gateway GW after the lapse of a prescribed time to release the connection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, PHS
The present invention relates to a mobile data communication system capable of performing data communication between a mobile terminal device and a server device connected to a communication network using a (Personal Handy-phone System), and a mobile terminal device and a data communication device.

[0002]

2. Description of the Related Art In recent years, digital mobile communication systems represented by PHS have rapidly spread. In this type of system, in addition to the voice call service, the provision of a data communication service using a personal computer connected to a mobile phone as a mobile terminal device or a portable information terminal having a wireless communication function has started.

For example, when a user wants to obtain desired information from an information provider on a computer network such as the Internet, a call is made from the portable information terminal to the desired information provider. Then, first, the portable information terminal and the nearest base station are connected via a wireless line, and then the server device of the information provider is accessed from this base station via a public network and the Internet.
Then, when a connection for data communication is established between the portable information terminal and the server device, information corresponding to the request of the portable information terminal is transmitted from the server device to the portable information terminal via the connection.

By the way, in the above mobile communication system, the mobile terminal device moves during a voice call with another device, etc.
When a base station to be connected is switched, an exchange on a communication network including a wired line switches communication paths. However, in data communication, when a mobile terminal device has to be switched to another base station due to a factor such as movement or failure or lack of available wireless resources during data communication with a server device, a base station to be connected to Is switched, the connection set on the communication network between the base station and the server device cannot be switched. For this reason, when performing data communication with the server device again, it is necessary to re-establish the connection via another base station by performing call processing again on the user side. In other words, it is necessary to constantly monitor whether or not the base station has been switched on the user side, and if the base station has been switched, call processing must be performed by the user. In this call processing, the old connection cannot be released.

[0005] In the above mobile communication system, if a method of reestablishing a connection via another base station is used, if a malicious user connects while pretending to be a reconnection during connection, spoofing may be performed. There is a fear that it can be done.

[0006]

As described above, in the above mobile communication system, when a base station is switched during data communication between a mobile terminal device and a server device, the mobile station is set on a communication network in accordance with the switching. The inconvenience that the switched connection and the old connection cannot be released cannot be performed. In addition, if a method of reestablishing a connection via another base station in accordance with base station switching is used, impersonation can be performed when a malicious user connects while pretending to be a reconnection during connection. There are also problems.

[0007] Therefore, an object of the present invention is to release an old connection regardless of a user operation to perform data communication even when a base station is switched during data communication between a mobile terminal device and a data communication device. It is an object of the present invention to provide a mobile data communication system and a mobile terminal device and a data communication device that can continue and prevent impersonation by a malicious user.

[0008]

SUMMARY OF THE INVENTION The present invention provides at least one base station device constituting a wireless area, a mobile terminal device connected to the base station device via a wireless line, a base station device and a wired line. The present invention is directed to a mobile data communication system that includes a data communication device connected via a communication network including a communication terminal and performs data communication by setting a connection between a mobile terminal device and the data communication device.

In order to achieve the above object, when a mobile terminal device performs data communication between the mobile terminal device and a data communication device in a state where a connection is set, the mobile terminal device transmits the data communication device. Means for transmitting determination information for determining whether the connection is a new connection or a reconnection to the data communication device via the base station device as a connection request signal, wherein the data communication device Receiving the connection request signal, the connection state determination means for determining whether the mobile terminal device that has made the connection is a new connection or a reconnection, and the data communication device and the base station device perform the connection state determination. Means for releasing the connection between the base station apparatus and the data communication apparatus that were connected before the reconnection when the connection is determined to be a reconnection. And so as to constitute Te.

According to this configuration, when the mobile terminal device performs data communication between the mobile terminal device and the data communication device, whether the device itself is a new connection or a reconnection to the data communication device. Is transmitted as a connection request signal to the data communication device via the base station device, so that the data communication device receives the connection request signal so that the mobile terminal device can perform data communication. It is possible to determine whether the device is a new connection or a reconnection due to base station switching, and if the result of this determination is a reconnection, release the connection with the base station device before reconnection. I can do it. That is, it is possible to provide the data communication device with a function of releasing the connection.

As a result, when the base station is switched due to the movement of the user or the like, the user does not need to perform any operation, and the mobile terminal only sends the discrimination information indicating the reconnection as the connection request signal. The data communication device can release the connection with the base station before reconnection efficiently and at a timing earlier than that of the conventional method. Therefore, data communication between the mobile terminal device and the data communication device can be performed. It is possible to continue.

Further, according to the present invention, in the above object, when the mobile terminal device performs data communication with the data communication device in a state where the connection is set, the mobile terminal device establishes a new connection with the data communication device. Means for transmitting, as a connection request signal, discrimination information for discriminating whether there is a connection request or a reconnection to the data communication device via the base station device. By receiving the connection state determination means for determining whether the mobile terminal device is a new connection or a reconnection to the data communication device, if the connection state determination means is determined to be a reconnection, The connection state of the mobile terminal device to the base station device was confirmed between the data communication device and the base station device before reconnection or the mobile terminal device connected to the base station device. Performs exchange of the connection state confirmation information necessary, based on the given and received connection state confirmation information,
The connection is selectively released between the base station device and the data communication device connected before the reconnection or between the base station device and the data communication device at the time of the reconnection.

[0013] According to this configuration, when the mobile terminal device that has requested the connection is re-connected, the data communication device transmits connection state confirmation information necessary for checking the connection state of the mobile terminal device that has requested the connection. Whether or not the mobile terminal device that has retransmitted and transmitted between itself and the base station device before reconnection and between the base station device and the mobile terminal device connected to the base station device has correctly requested reconnection. By confirming whether or not the mobile terminal device that has requested reconnection is a legitimate user, it can be determined whether or not the base station device before reconnection or based on the determination result. It is possible to release the connection with the base station device at the time of reconnection.

As a result, when a malicious user attempts to establish a connection by pretending to be a reconnection during the data communication of a legitimate user, it is possible to check and prevent this spoofing, and thereby the security of the entire system is ensured. Can be improved.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of a mobile data communication system according to the present invention, and CS1 to CSn indicate base stations. These base stations CS1 to CSn are geographically distributed in a service area covered by the system,
Each forms a wireless area called a cell.

The mobile terminals PS1 to PSm are connected to the nearest base station via a radio line in the cell formed by each of the base stations CS1 to CSn. As a wireless access method between the base station and the mobile terminal device, for example, TDMA-TDD (Time Division Multiple Access-
Time Division Duplex) method is used. The mobile terminal devices PS1 to PSm include a mobile information terminal having a data communication function and a wireless access function, and a mobile terminal device having a personal computer PC connected to the mobile phone, in addition to a mobile phone having only a call function.

Each of the base stations CS1 to CSn is connected to a communication network via a wired line. The communication network is an integrated services digital network (ISDN) IN1 and this IDN.
An I 'interface network IN2 for accommodating each of the base stations CS1 to CSn in the SDN IN1, and a dedicated line network P
N. A computer network, an in-house network, and the like are connected to the communication network in addition to many subscriber wire terminal devices. In addition, the ISDN IN1 and the leased line network PN have a gateway G as a data relay device.
W is connected, and the server apparatus AS is connected via the gateway GW. Therefore, when using the Internet, the mobile terminal device PS as well as the subscriber wire terminal can be used by using the TCP / IP protocol.
Access is also possible from 1 to PSm.

Further, the server apparatus AS has a function of downloading various information in response to a request from the subscriber wired terminal and the mobile terminal apparatuses PS1 to PSm. Next, the configuration and operation of each device in one embodiment of the mobile data communication system will be described with reference to FIGS. FIG. 2 is a circuit block diagram of the mobile terminal devices PS1 to PSm, and FIG. 3 is a circuit diagram of the base stations CS1 to CSn.
FIG. 4 is a circuit block diagram of the gateway GW.
FIG. 3 is a circuit block diagram of FIG.

First, the configuration of each of the mobile terminals PS1 to PSm will be described with reference to FIG. 2. The radio unit 1 having the antenna 11, the modem unit 2, the TDMA unit 3, the communication unit 4, the control unit 5, information storage unit 6, data communication unit 7
And

That is, the radio carrier signals arriving from the base stations CS1 to CSn are received by the antenna 11, and then input to the receiving unit 13 via the high frequency switch (SW) 12 of the radio unit 1. In the receiving unit 13, the received radio carrier signal is mixed with the local oscillation signal generated from the synthesizer 14 and down-converted into a received intermediate frequency signal. The local oscillation signal frequency generated from the synthesizer 14 is instructed by the control unit 5 to a value corresponding to the radio channel frequency. Also, the wireless unit 1
Is provided with a reception field strength detection unit (RSSI) 16. In the reception electric field strength detection unit 16, the mobile station PS1
The received electric field strength of the wireless carrier signal arriving from .about.PSm is detected, and the detected value is notified to the control unit 5 to judge and display the reception quality, for example.

The received intermediate frequency signal output from the receiving unit 13 is input to the demodulation unit 21 of the modem unit 2. The demodulation section 21 performs digital demodulation of the received intermediate frequency signal, thereby reproducing a digital demodulated signal.

TDMA decoding section 31 of TDMA section 3
Separates the digital demodulated signal for each reception time slot. If the data of the separated slot is audio data, the audio data is transmitted to the interface unit 4.
To enter. On the other hand, if the data of the separated slot is unrestricted digital data or control data, these data are input to the data communication unit 7.

The communication unit 4 has an ADPCM (Adaptive Diffe
rential Pulse Code Modulation) Transcoder 41
, A PCM codec 42, a speaker 43, and a microphone 44. The ADPCM transcoder 41 decodes the audio data output from the TDMA decoding unit 31. The PCM codec 42 uses the A
The digital audio signal output from the DPCM transcoder 41 is converted into an analog signal, and this audio signal is output from the speaker 43 as loudspeaker.

The data communication unit 7 receives the data supplied from the code unit 31 by the TDMA, and supplies the data to the control unit 5. If the received data is control data, the control unit 5 analyzes the control data and performs necessary control.
On the other hand, if the received data is information data coming from a server or the like, this information data is stored in the information storage unit 6 and supplied to the display unit 8 for display.

On the other hand, the user's voice signal input to the microphone 44 is PCM-coded by the PCM codec 42 and then compression-coded by the ADPCM transcoder 41. Then, the encoded audio data is TDM
It is input to the A encoding unit 32. The control data and information data output from the control unit 5 are input to the TDMA encoding unit 32 via the data communication unit 7.

[0026] The TDMA encoding unit 32 uses the ADP
The digital audio data of each channel output from the CM transcoder 41 and the control data and information data output from the data communication unit 7 are inserted into a transmission time slot designated by the control unit 5 and multiplexed. Modulation unit 2
2 digitally modulates the transmission intermediate frequency signal with the multiplexed digital communication signal output from the TDMA encoding unit 32, and inputs the modulated transmission intermediate frequency signal to the transmission unit 15.

The transmitting section 15 mixes the modulated transmission intermediate frequency signal with the local oscillation signal generated from the synthesizer 14, upconverts the mixed signal into a radio carrier frequency, and further amplifies the signal to a predetermined transmission power level. The radio carrier signal output from the transmitting unit 15 is transmitted from the antenna 11 via the high frequency switch 12 to the base stations CS1 to CSn.
Sent to

The control unit 5 includes, for example, a microcomputer as a main control unit. The control unit 5 has a wireless connection control function, a call control function, a data communication control function, and the like that perform processing according to a program stored in the information storage unit 6. , Connection request transmission control means 51 and connection confirmation information communication control means 52
And

The connection request transmission control means 51 includes:
When the own device performs data communication with the server device AS, the base stations CS1 to CSn are used as connection request signals to determine whether the own device is a new connection or a reconnection to the server device AS. Via the gateway GW. Further, the connection confirmation information communication control means 52 performs connection state confirmation necessary for confirming the connection state of the own apparatus coming from the base stations CS1 to CSn when the base station is switched due to the movement of the own apparatus. When the request signal is received, a response signal indicating the connection state of the own device to the base stations CS1 to CSn is transmitted to the base stations CS1 to CSn.

Reference numeral 9 in the figure denotes an input unit containing a dial key, a transmission key, various function keys, a handwriting input unit, and the like. Next, the configuration of the base stations CS1 to CSn is shown in FIG.
This will be described with reference to FIG.

The base stations CS1 to CSn are connected to the antenna 111
, A modem unit 20, and a TDMA unit 3.
0, an interface unit 40, a control unit 50, an information storage unit 60, and a data communication unit 70.

That is, the radio carrier signals arriving from the mobile terminal devices PS1 to PSm are received by the antenna 111 and then input to the receiving unit 113 via the high frequency switch (SW) 112 of the radio unit 10. The receiving unit 113 converts the received wireless carrier signal into the synthesizer 11
4 and down-converted into a received intermediate frequency signal. The local oscillation frequency generated by the synthesizer 114 is instructed by the control unit 50 according to the radio channel frequency. Also, the radio unit 10 includes a reception field strength detection unit (RSSI) 1
16 are provided. This reception electric field strength detection section 116
Then, the received electric field strength of the radio carrier signal arriving from the mobile terminal devices PS1 to PSm is detected, and the detected value is notified to the control unit 50 for a free channel search, a handover of the mobile terminal device, and the like.

The received intermediate frequency signal output from the receiving section 113 is input to the demodulation section 221 of the modem section 20. The demodulation section 221 performs digital demodulation of the received intermediate frequency signal, thereby reproducing a digital demodulated signal.

The TDMA decoding section 33 of the TDMA section 30
1 separates the digital demodulated signal for each reception time slot. If the data of the separated slot is audio data, the audio data is input to the interface unit 40. On the other hand, if the data of the separated slot is unrestricted digital data or control data, these data are input to the data communication unit 70.

The interface unit 40 has an ADPCM (Ad
An aptive Differential Pulse Code Modulation) transcoder 441, a public line interface 442, and a dedicated line interface 443. ADPC
The M transcoder 441 is connected to the TDMA decoding unit 3
The audio data output from 31 is decoded. ADP above
The digital audio signal decoded by the CM transcoder 441 is transmitted from the public line interface 442 to the I ′ network IN.
2 is sent. The public line interface 442 performs call connection processing and data communication with the I ′ network IN2 in accordance with an instruction from the control unit 50. Dedicated line interface 44
3 performs call connection processing and data communication with the leased line network PN in accordance with an instruction from the control unit 50.

The data communication unit 70 is connected to the mobile terminal PS1.
If the data arriving from .about.PSm is control data addressed to the own station, the control data is input to the control unit 50. Control unit 5
0 performs connection connection control and data transfer control based on TCP / IP, which will be described later, based on the control data.
On the other hand, if the data arriving from the mobile terminal devices PS1 to PSm is data addressed to the external communication network, the data communication unit 7
0 transfers this data to the I 'network IN2 or the private line network PN via the public line interface 442 or the private line interface 443.

On the other hand, digital communication signals of a plurality of channels arriving from the I 'network IN2 are received by the public line interface 442, respectively. If the digital communication signal is audio data, the digital communication signal is subjected to compression encoding processing by the ADPCM transcoder 441 and is input to the TDMA encoding unit 332. On the other hand, if the digital communication signal is control data or information data, it is input to the data communication unit 70.

The data communication unit 70 determines that the destination of the input control data and information data is
Sm, the control data and the information data are
Input to the A encoding unit 332. On the other hand, if the input data is data addressed to the own station, the data is input to the control unit 50. The control unit 50 analyzes the input data and performs various controls. Further, the control unit 50 inputs control data addressed to the mobile terminal devices PS1 to PSm to the TDMA encoding unit 332 via the data communication unit 70.

The digital communication signals of a plurality of channels arriving from the leased line network PN are
Each of them is received at 43, and thereafter inputted to the data communication unit 70. If the destination of the control data and information data included in the input digital communication signal is the mobile terminal device PS1 to PSm, the data communication unit 70 encodes the control data and information data into the TDMA encoding unit 3.
Enter 32. On the other hand, if the input data is data addressed to the own station, the data is input to the control unit 50. The control unit 50 analyzes the input data and performs various controls. The control unit 50 includes the mobile terminal devices PS1 to PS1.
The control data addressed to PSm is input to the TDMA encoding unit 332 via the data communication unit 70.

[0040] The TDMA encoding unit 332 converts the AD
The digital audio data of each channel output from the PCM transcoder 441 and the information data and control data output from the data communication unit 70 are inserted and multiplexed in the transmission time slot specified by the control unit 50. The modulating unit 222 is configured by the TDMA encoding unit 332
The transmission intermediate frequency signal is digitally modulated by the multiplexed digital communication signal output from, and the modulated transmission intermediate frequency signal is input to transmission section 115.

The transmitting section 115 mixes the modulated transmission intermediate frequency signal with the local oscillation signal generated from the synthesizer 114, upconverts the signal into a radio carrier frequency, and further amplifies the signal to a predetermined transmission power level. The wireless carrier signal output from the transmitting unit 115 is transmitted from the antenna 111 to the mobile terminal devices PS1 to PSm via the high frequency switch 112.

The control unit 50 has a microcomputer as a main control unit. Its control functions include a wireless control unit 551 and a connection confirmation information communication control unit 552.
And connection processing control means 553.

The wireless control means 551 is provided for the mobile terminal PS.
For example, transmission / reception of connection state confirmation information necessary for confirming the connection state of the mobile terminal devices PS1 to PSm is performed between the mobile terminals 1 to PSm via a wireless line. In addition, the radio control means 551 determines whether or not a mobile terminal device in its own cell is in use in order to continue data communication even when the mobile terminal devices PS1 to PSm move. It manages reception of a connection status confirmation request signal from the GW and transmission of a connection status confirmation response signal from the mobile terminal devices PS1 to PSm.

The connection confirmation information communication control means 552 exchanges connection state confirmation information with the gateway GW via a connection established on the communication network. The connection processing control means 553 is based on the connection states of the mobile terminals PS1 to PSm obtained by the exchange of the connection state confirmation information by the wireless control means 551 and the connection confirmation information communication control means 552. Release or open a connection to The wireless control unit 551, the connection confirmation information communication control unit 552, and the connection processing control unit 553
Executes a control process according to a protocol execution program stored in the information storage unit 60.

Next, the gateway GW shown in FIG.
This will be described with reference to FIG. That is, the gateway GW
A line interface unit 711, a dedicated line interface unit 712, a packet communication control unit 713, a routing table unit 714, a buffer unit 715, a network interface unit 716, and a device control unit 717 are provided. These circuits are connected to each other via a control bus.

Here, the line interface unit 711 is
In accordance with an instruction from the device control unit 717, call connection processing and data communication are performed for a circuit switching network that integrates the ISDN IN1 and the I 'network IN2. The leased line interface unit 712, in accordance with the instruction of the device control unit 717,
A call connection process and data communication for N are performed. The network interface unit 716 performs a call connection process and data communication with the server device AS in accordance with an instruction from the device control unit 717.

The packet communication control unit 713 stores the packet data coming from the server device AS in the packet storage unit 71.
31. Then, in accordance with an instruction from the device control unit 717, if the data arrived from the server device AS is control data addressed to the own device, the control data is input to the device control unit 717. Then, the device control unit 717 performs connection connection control, data transmission control, and the like based on the control data. On the other hand, if the data arriving from the server device AS is data addressed to the external communication network, the packet communication control unit 713 transmits the data to the communication network via the line interface unit 711 or the dedicated line interface unit 712.

The buffer unit 715 is provided with a line interface unit 711 or a dedicated line interface unit 712.
Stores data arriving via. Here, when the incoming data is control data addressed to the own device, the control data is input to the device control unit 717, and thereafter, the connection connection or release control with the base station devices CS1 to CSn and the data are controlled. Used for processing such as transmission control.

The device control section 717 performs overall control of each circuit using the microcomputer as a main control section. The apparatus control section 717 further includes a connection state determination section 717a, a connection confirmation information communication control section 717b, and a connection processing control section. Means 717c.

The connection state judging means 717a receives connection request signals arriving from the mobile terminal devices PS1 to PSm, and receives the connection request from the mobile terminal devices PS1 to PSm.
Is a new connection or a reconnection to the server apparatus AS.

When the connection state determination means 717a determines that the connection is reconnection, the connection confirmation information communication control means 717b sets a connection between the own apparatus and the mobile terminal apparatus connected to the base stations CS1 to CSn before reconnection. Then, connection state confirmation information necessary for confirming the connection state of the mobile terminal apparatus is transmitted and received between the own apparatus and the mobile terminal apparatuses connected to the base stations CS1 to CSn before reconnection.

The connection processing control means 717c, based on the connection status of the mobile terminal devices PS1 to PSm obtained by the connection confirmation information communication means 717b, establishes a connection between the base station before reconnection and its own device or a base station at the time of reconnection. Control of opening or releasing a connection is performed between the station and the own device. The connection processing control unit 717c also manages connection switching in order to continue data communication even when the mobile terminal devices PS1 to PSm move. Further, after the connection is opened or released, routing information including information indicating a data transmission path between the mobile terminal devices PS1 to PSm and the server device AS is created or changed, and stored in the routing table unit 714. I do. That is, the device control unit 7
17 controls data communication between the mobile terminal devices PS1 to PSm and the server device AS based on the created or changed routing information.

Next, the data communication operation and connection release processing by the system configured as described above will be described. Here, the mobile terminal device PS1 is connected to the base station CS.
1 performs data communication with the server device AS in the cell 1, and the mobile station device PS1 performs the data communication with the base station C during the data communication.
The case where the cell moves into the cell of S2 will be described as an example. FIG. 5 is a sequence diagram showing the procedure.

That is, when the mobile terminal device PS1 calls the server device AS, a call connection is established between the base station CS1 and the mobile terminal device PS1, and a connection is established between the base station CS1 and the gateway GW. Is established as connection A. And the mobile terminal device PS
1 transmits a connection request signal indicating that the connection is a new connection to the base station C
The gateway GW is notified via S1. The gateway GW determines that the mobile terminal device PS1 is a new connection to the server device AS by receiving the incoming connection request signal. Thereafter, data communication can be performed between the mobile terminal device PS1 and the server device AS via the connection A.

Thereafter, when the mobile terminal device PS1 moves into the cell of the base station CS2 due to the movement of the user or the like, the mobile terminal device PS1 makes a call to the server device AS, so that the base station CS2 and the mobile terminal A call connection is established with the device PS1, and a connection B is established between the base station CS2 and the gateway GW.

Then, the mobile terminal device PS1 is connected to the base station C
A connection request signal indicating reconnection is sent to the gateway GW via S2. Upon receiving the connection request signal, the gateway GW sends the connection request to the mobile terminal device PS1.
After recognizing that the connection is a reconnection, disconnecting the connection A, control is performed so that data communication is performed between the mobile terminal device PS1 and the server device AS using the connection B.

In the above sequence, the connection status confirmation and the connection release of the mobile terminal device PS1 may be performed after the reconnection of the mobile terminal device PS1 is completed, or the connection status confirmation after the reconnection is performed. The connection may be released. In either case, the connection release processing can be performed at an earlier timing than in the conventional method of starting from the mobile terminal device PS1.

For a new connection request or a reconnection request in a wireless section, a communication channel for performing data communication may be used, or a wireless control channel may be used.

Next, in the data communication operation of the system, the mobile terminal device PS1 performs the data communication with the base station CS.
An example in which the connection status of the mobile terminal device PS1 has been confirmed from the gateway GW when the mobile terminal device has moved into the cell No. 2 will be described. FIG. 6 is a sequence diagram showing the procedure. The description of the same operation as in FIG. 5 is omitted.

In FIG. 6, upon receiving a connection request signal indicating reconnection from the mobile terminal device PS1, the gateway GW inquires of the mobile terminal device connected to the base station CS1 before reconnection that connection has been confirmed. . That is, the gateway GW transfers the connection state confirmation request signal to the base station CS1 before reconnection via the connection A. Then, the base station CS1 sends out a connection state confirmation request signal to the mobile terminal device existing in the cell of the base station via the radio line. If no response is returned from the mobile terminal device, the base station CS1 waits for a predetermined time (T0) to elapse,
Confirm that there is no response, and send a negative response to Gateway G
Send to W Thereafter, the base station CS1 and the gateway G
Connection A is released with W.

FIG. 7 shows an example of a case where a mobile terminal device in the cell of the base station CS1 before reconnection returns a response in the above sequence. That is, when receiving the connection request signal indicating the reconnection from the mobile terminal device PS1, the gateway GW inquires of the base station CS1 before the reconnection via the connection A about the connection confirmation. When receiving the connection state confirmation request signal from the base station CS1, the mobile terminal device PS1 outputs a negative acknowledgment signal to the base station CS1.
Return to 1. Hereinafter, this negative acknowledgment signal is transmitted to the base station CS.
1 is transferred to the gateway GW and subjected to connection A release processing. Therefore, it is possible to release the connection A between the base station CS1 and the gateway GW at an earlier timing than in the above sequence example.

FIG. 8 shows an example in which an unauthorized terminal is rejected in the above sequence. That is, when the unauthorized terminal attempts to impersonate by requesting reconnection to the gateway GW, the gateway GW sends a connection state confirmation request signal to the base station CS1 before reconnection via the connection A. And the mobile terminal device PS1
Is connected to the base station CS1, and when receiving the connection state confirmation request signal, transmits an acknowledgment signal to the base station C1.
Return to gateway GW via S1.

For this reason, the gateway GW receives the acknowledgment signal, recognizes that the mobile terminal device that has requested the reconnection is an unauthorized terminal, releases the connection B with the base station CS2, and releases the unauthorized connection. Unauthorized use by the terminal can be prevented. Further, the gateway GW can ensure stronger security by combining the terminal verification processing using the personal identification number when establishing the connection.

In the above sequence examples of FIGS. 6 to 8, the terminal connection confirmation, the negative response, and the confirmation response in the wireless section may use a communication channel for performing data communication. It is also possible to use Further, the connection request signal for new connection / reconnection in the examples of FIGS. 5 to 8 can be sent to the gateway GW at the time of call connection / connection establishment.

FIG. 9 is a flowchart showing the operation of the gateway GW. That is, the gateway GW
Receives a connection request signal from the mobile terminal device PS1 and receives the connection request signal (step S11),
It is determined whether the mobile terminal device PS1 is a new connection or a reconnection to the server device AS (step S12).
Here, when it is determined that the connection is a new connection, the mode shifts to the data communication mode (step S13). If it is determined that the connection is a reconnection, a connection state confirmation request signal is transmitted to the base station CS1 before the reconnection using the old connection (step S14). And the base station C before reconnection.
The acknowledgment signal returned from S1 is received, and analysis is performed to determine whether the content of this signal is an acknowledgment or a negative acknowledgment (step S15). Here, if the response is a negative response, the old connection is released and changed to a new connection (step S16). If the response is an acknowledgment,
The old connection is maintained and the new connection is released (step S17).

As described above, in the above-described embodiment, when the mobile terminal device PS1 performs data communication with the server device AS, the mobile terminal device PS1 is newly connected or reconnected to the server device AS. Is transmitted to the gateway GW via the base stations CS1 to CSn as connection request signals to determine whether or not the mobile terminal device PS1 receives the connection request signal. It is possible to determine whether the server device AS is a new connection or a reconnection due to base station switching. If the result of this determination is a reconnection, for example, release of the connection with the base station CS1 before the reconnection is performed. So they can do it. That is, it is possible to give the function of releasing the connection to the gateway GW.

For this reason, when the base station is switched due to the movement of the user or the like, the user does not need to perform any operation, and the mobile terminal apparatus PS1 only needs to send the discrimination information indicating the reconnection as the connection request signal. , Gateway GW
It is possible to efficiently release the connection with the base station CS1 before reconnection and at a timing earlier than the conventional method of releasing the connection by the operation of the user, and furthermore, the mobile terminal apparatus PS1 and the server apparatus AS.
It is possible to continue data communication with the device.

Also, according to the above embodiment, when gateway GW determines that reconnection is to be performed, gateway GW determines whether or not mobile terminal device PS1 exists in the cell of base station CS1 before reconnection. The connection state confirmation information necessary for confirming whether the connection request is legitimate is transmitted between the base station CS1 before reconnection via the old connection and the mobile terminal device PS1 in the cell of the base station CS1. And confirms whether or not the reconnected mobile terminal device PS1 has correctly made a connection request, thereby determining whether or not the mobile terminal device that has requested reconnection belongs to an authorized user. Base station CS1 before reconnection based on this determination result.
Alternatively, the connection with the base station CS2 at the time of reconnection can be released.

For this reason, if a malicious user attempts to establish a connection by pretending to be a reconnection during the data communication of a legitimate user, this spoofing can be checked and prevented, and therefore, the security of the entire system can be improved. Improvement can be achieved.

In the above embodiment, the case where data communication is performed between the mobile terminal devices PS1 to PSm and the server device AS has been described as an example. However, the present embodiment is connected to a WWW server on the Internet or a communication network. When performing data communication with the server, it is also possible to execute connection establishment or release processing according to base station switching.

It should be noted that the present invention is not necessarily limited to the scope of each of the above-described embodiments, and it is needless to say that various modifications can be made without departing from the scope of the invention.

[0072]

As described in detail above, according to the present invention,
When the mobile terminal device reconnects to the data communication device via another base station device due to movement or the like, a setting is made between the base station device connected before the reconnection and the data communication device. The released connection can be efficiently released. In addition, by checking the connection state of the mobile terminal device when releasing the connection, it is possible to improve security against impersonation of a malicious user.

Therefore, even when the base station is switched during data communication between the mobile terminal device and the data communication device, the old connection is released and the data communication is continued irrespective of the operation of the user. And a mobile terminal device and a data communication device that can prevent spoofing by the mobile data communication system.

[Brief description of the drawings]

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

FIG. 2 is a circuit block diagram showing a configuration of a mobile terminal device of the system shown in FIG.

FIG. 3 is a circuit block diagram showing a configuration of a base station of the system shown in FIG. 1;

FIG. 4 is a circuit block diagram showing a configuration of a gateway of the system shown in FIG. 1;

FIG. 5 is a diagram illustrating release of a connection when a mobile terminal device performs data communication with a server device in a cell of a base station and the mobile terminal device moves into a cell of another base station during data communication. The figure which shows the sequence performed.

FIG. 6 is a diagram showing a sequence for releasing a connection when the connection state of the mobile terminal device is confirmed from the gateway when the mobile terminal device moves into a cell of another base station during data communication.

FIG. 7 is a diagram showing another example of the sequence in FIG. 6;

FIG. 8 is a diagram showing an example in which an unauthorized terminal is rejected in the sequence of FIG. 6;

FIG. 9 is a flowchart illustrating an operation of the gateway in the sequence of FIG. 6;

[Explanation of symbols]

 CS1 to CSn base station PS1 to PSm mobile terminal device IN1 ISDN IN2 I 'network PN dedicated line network AS server device GW gateway 1,10 radio unit 2,20 modem unit 3,30 TDMA Unit 4, 40 Talk unit 5, 50 Control unit 6, 60 Information storage unit 7, 70 Data communication unit 11, 111 Antenna 12, 112 High frequency switch (SW) 13, 113 Receiving unit 14, 114 ... Synthesizers 15,115 ... Transmission sections 16,116 ... Reception electric field strength detection sections (RSSI) 21,221 ... Demodulation sections 22,222 ... Modulation sections 31,331 ... TDMA decoding sections 32,332 ... TDMA encoding sections 41,441 ... ADPCM transcoder 42 PCM codec 43 Speaker 44 Microphone 442 Public line interface Source unit 443... Dedicated line interface unit 51... Connection request transmission control unit 52... Connection confirmation information communication control unit 551... Wireless control unit 552. Packet communication control unit 714 Routing table unit 715 Buffer unit 716 Network interface unit 717 Device control unit 717a Connection state determination unit 717b Connection confirmation information communication control unit 717c Connection processing control unit

Claims (9)

[Claims] At least one base station device constituting a wireless area, a mobile terminal device connected to the base station device via a wireless line, and a communication network including the base station device and a wired line In a mobile data communication system comprising a data communication device to be connected and performing data communication by setting a connection between the mobile terminal device and the data communication device, the mobile terminal device sets the connection In the state, when performing data communication between the mobile terminal device and the data communication device, determination information for allowing the own device to determine whether the data communication device is a new connection or a reconnection is provided. Means for transmitting a connection request signal to the data communication device via the base station device, wherein the data communication device receives a connection request signal from the mobile terminal device. By receiving the connection state, the mobile terminal apparatus includes a connection state determination unit that determines whether the mobile terminal apparatus is a new connection or a reconnection, and the data communication apparatus and the base station apparatus use the connection state determination unit. Mobile data characterized by comprising connection release means for releasing a connection between the base station apparatus connected before the reconnection and the data communication apparatus when the connection is determined to be a reconnection. Communications system. 2. At least one base station device constituting a wireless area, a mobile terminal device connected to the base station device via a wireless line, and a communication network including the base station device and a wired line In a mobile data communication system comprising a data communication device to be connected and performing data communication by setting a connection between the mobile terminal device and the data communication device, the mobile terminal device sets the connection In the state, when performing data communication between the mobile terminal device and the data communication device, determination information for allowing the own device to determine whether the data communication device is a new connection or a reconnection is provided. Means for transmitting a connection request signal to the data communication device via the base station device, wherein the data communication device requires a connection request coming from the mobile terminal device. By receiving a signal, connection state determination means for determining whether the mobile terminal device that has requested connection is a new connection or a reconnection, and if the connection state determination means determines that reconnection, Between the data communication device and the base station device before reconnection or the mobile terminal device connected to the base station device,
Confirmation information communication means for transmitting and receiving connection state confirmation information necessary for confirming the connection state of the mobile terminal device to the base station apparatus; and based on the connection state confirmation information transmitted and received by the confirmation information communication means, Connection processing means for selectively releasing a connection between the base station apparatus before the connection and the data communication apparatus or between the base station apparatus and the data communication apparatus at the time of reconnection. Characteristic mobile data communication system. 3. The base station device before reconnection or the base station device connected to the confirmation information communication unit from the data communication device when the connection state determination unit determines that the connection is reconnection. When the connection state confirmation request signal is transferred to the mobile terminal apparatus, the base station apparatus before reconnection or the mobile terminal apparatus connected to this base station apparatus receives the connection state confirmation request signal, and then reconnects the mobile terminal apparatus. A function of transmitting a response signal indicating whether or not a connection state to the base station apparatus before connection is maintained to the data communication apparatus, wherein the connection processing means is configured to transmit the base station before reconnection by the confirmation information communication means; If the response signal transferred from the station device to the data communication device indicates that the connection state is not maintained, the connection between the base station device and the data communication device before reconnection is released. Mobile data communication system according to claim 2, characterized in that it has a function of. 4. The connection processing means, when a response signal transferred from the base station apparatus before reconnection to the data communication apparatus by the confirmation information communication means indicates that the connection state is maintained, 4. The mobile data communication system according to claim 3, further comprising a function of releasing a connection between the base station device and the data communication device at the time of connection. 5. The confirmation information communication means transmits and receives connection state confirmation information between a base station apparatus before reconnection and a mobile terminal apparatus connected to the base station apparatus by using a radio control channel. The mobile data communication system according to claim 2, wherein the mobile data communication is performed. 6. A connection between at least one base station device forming a wireless area via a wireless line and a data communication device connected to the base station device via a communication network including a wired line. In a mobile terminal device that performs data communication by setting a connection state confirmation request signal required to confirm the state of the own device coming from the base station device, A confirmation information communication control unit that sends a response signal indicating a connection state to the base station device, by transferring the response signal from the base station device to the data communication device, before the data communication device reconnects. Between the base station device and the data communication device or between the base station device and the data communication device at the time of reconnection,
A mobile terminal device characterized in that a connection can be selectively released. 7. The confirmation information communication control means receives the connection state confirmation request signal using a radio control channel with the base station apparatus, and transmits the response signal. Item 7. The mobile terminal device according to Item 6. 8. The base station apparatus according to claim 1, wherein said confirmation information communication control means receives a connection state confirmation request signal from said base station apparatus and, when connected to another base station apparatus, sends a negative acknowledgment signal to said base station apparatus. The mobile terminal device according to claim 6, wherein the mobile terminal device is returned. 9. Connected to at least one base station device forming a wireless area via a communication network including a wired line,
In a data communication device that performs a data communication by setting a connection between the base station device and a mobile terminal device connected via a wireless line, by receiving a connection request signal coming from the mobile terminal device, Connection state determining means for determining whether the mobile terminal apparatus is a new connection or a reconnection to the own apparatus; and if the connection state determination means determines that the mobile terminal apparatus is a reconnection, before the mobile apparatus is reconnected, Confirmation information communication for performing control for transmitting and receiving connection state confirmation information necessary for confirming a connection state of the mobile terminal device to the base station device with a mobile terminal device connected to the base station device Control means, based on the connection state confirmation information exchanged by the confirmation information communication control means, between the base station apparatus before reconnection and the own apparatus or between the base station apparatus at reconnection and the self apparatus. Between the location, communication device, characterized by comprising; and a connection processing control means for selectively releasing the connection.