JP2001045540A - Mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile communication system that manages mobile terminals in the unit of groups so as to make specification of a position of a user of a mobile terminal difficult. SOLUTION: In this mobile communication system, a public key table in an HLR shown in Figure (a) indicates arrangement of sets of terminal identification numbers (TID) and public keys (PKx) of terminals and the value of a public key of a terminal can be acquired from this table by using a TID for a key. A position information table indicates arrangement of sets of terminal group identification numbers (GID) and position information sets of a plurality of terminals belonging to the GID. The position information (LI) of memory in the mobile terminal shown in Figure (b) is position information in the case of registering a position to the HLR, and own terminal private key (SK) is a private key corresponding to the public key stored in the public key table in the HLR.

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 in which it is difficult to specify the position of a mobile terminal user in a mobile communication system.

[0002]

2. Description of the Related Art Conventionally, SCIS (Symposium on Cryptography)
and Information Security) '97 -27B "Privacy of location and its management, Matsumoto, Shimizu, Okamoto" Appendix A "About mobile phone", the following examples are listed as methods to make it difficult to specify the location.

First, it is assumed that an electronic cash method is used as a prepaid card. The electronic cash card can be inserted into the terminal. When making a call, electronic cash is sent to the mobile communication company. It is assumed that the electronic cash used here is in a secure system. Also, the investigating body with the permission of the court shall be able to know the correspondence between the terminal identification number and the terminal holder.

Next, the following conditions are set as a system. The mobile communication company records the terminal identification number on the mobile phone and passes it to the store. The user purchases a mobile phone at a store. The user inserts the electronic cash card into the terminal and makes a call.
When making a mobile phone call, the terminal identification number is used as the telephone number. The mobile carrier verifies the validity of the electronic cash and allows the call. In a criminal investigation, the investigating agency specifies the name from the terminal identification number.

[0005]

However, once the correspondence between the terminal identification number and the terminal holder is known, there is a possibility that who can find out who is where by inquiring the mobile communication company, and if a telephone directory exists. It also states that there is a problem that it is possible to know the correspondence between the terminal identification number and the terminal holder. This is because terminal location information is managed on a terminal-by-terminal basis.

In order to solve the above-mentioned conventional problems, the present invention provides a mobile communication system in which it is difficult to specify the position of a mobile terminal user by managing mobile terminals in the mobile communication system on a group basis. The purpose is to provide.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plurality of mobile terminals, a plurality of base stations which wirelessly communicate with these mobile terminals in their service areas, In a mobile communication system having an exchange having a call control function to said mobile terminal via a station and a home location register having an in-network database function for managing communication service information for said mobile terminal, said home location register However, each mobile terminal belonging to the group is located in a public key table storing a public key corresponding to a terminal identification number indicating each mobile terminal, and a terminal group identification number in which the plurality of mobile terminals are grouped. A location information table that stores location information indicating the service area of each of the base stations, and the mobile terminal, The exchange has a memory for storing the location information to which the user belongs and a secret key corresponding to the public key, and the exchange refers to a public key table and a location information table of the home location register to control a call to the mobile terminal. Is performed.

[0008] With the above arrangement, the information relating to the location of the mobile terminal is managed by the terminal group identification number, and as a call control, the terminal responding to the call signal encrypts its own terminal identification number with the public key of the calling terminal and sends it out. However, the terminal identification number of the terminal to which the calling terminal has responded can be decrypted with the secret key.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration example of a mobile communication network according to the present invention. The location information of the service area by the base station 11
LI1, the location information of the service area by the base station 12
2, mobile terminal 1 is located in LI1 and mobile terminal 2 is in LI1.
2 is located.

Each mobile terminal has a uniquely identifiable terminal identification number (TID). A part of the terminal identification number (TID) is masked and set to "0" to be a terminal group identification number (GID).

FIG. 2 shows the relationship between the terminal identification number (TID) and the terminal group identification number (GID). For example, when masking the least significant bit, if TID = 0 or 1, GID = 0.
When masking lower 2 bits, if TID = 0-3, GID
= 0. The mask position may be, for example, several bits from the highest order, or may be arranged at discrete positions in 1-bit units.

FIG. 3A shows a home location register (hereinafter abbreviated as "HLR") having an in-network database function for managing communication service information for mobile terminals.
2 shows a configuration of a public key table and a position information table which are a part of internal data.

The public key table contains a terminal identification number (TID)
A set of the terminal and the public key (PKx) of the terminal is arranged. With this table, the value of the public key of the terminal can be obtained from the TID. For example, a pair of a “public key and a secret key” of a public key cryptosystem such as the RSA encryption is generated, and the public key which is one of the pairs is stored in this table. The corresponding secret key is stored in the mobile terminal memory as shown in FIG.

The location information table contains a terminal group identification number (GI
D) and a set of location information of multiple terminals belonging to this GID. The location information table is GI, not TID
Since D is used as an index, it becomes difficult for the HLR to grasp the location information of each mobile terminal.

Although a large number of data are stored in the HLR, only the configuration of the public key table and the position information table which are related to the operation of the present embodiment will be described here.

FIG. 3B shows an example of the configuration of the internal memory of the mobile terminal. The location information (LI) is the location information at the time of performing location registration in the HLR, and is updated each time the mobile terminal performs location registration. The own terminal secret key (SK) is shown in FIG.
This is a private key corresponding to the public key stored in the public key table in the HLR.

Next, the operation of this embodiment will be described.

In the following example, the processes of location registration, calling / calling, response / connection will be described with reference to FIGS. When the bit position of the mask is different, the processing flow itself is the same except for the value of the ID.

FIG. 4 shows a location registration process according to this embodiment. The signal between the mobile terminal and the HLR actually passes through a base station / switch as in the configuration example shown in FIG. 1, but is omitted here.

Each base station always reports the area position information.

The mobile terminal transmits the position information (hereinafter referred to as "new LI") reported by the base station and the position information (hereinafter referred to as "old LI") held in its own terminal memory shown in FIG. ) Are compared, and if a mismatch is detected, (1) own GID and (2)
A location registration signal having three parameters of the old LI and (3) the new LI is transmitted to the HLR.

When the HLR receives the position registration signal, it searches the position information table of FIG. 3 for the LI corresponding to the GID. L
There are a plurality of I. When masking the lower 2 bits, a maximum of 4
May be stored.

The HLR stores all the data stored corresponding to the GID.
The LI is compared with the sent old LI. If there is a matching LI, the old LI in the location information table is rewritten to the new LI. If there is no matching LI, the new LI is stored in an area corresponding to the GID in the location information table.
And rewrite the location information table. When rewriting to the new LI or addition of the new LI is completed, the HLR sends a location registration completion signal to the mobile terminal.

When the mobile terminal receives the location registration completion signal, the mobile terminal updates the location information held in its own terminal memory from the old LI to the new one.
Rewrite to LI.

In the following, a case where the mobile terminal i makes a call and talks with the mobile terminal 2 will be described.

FIG. 5 shows a process of originating a call and calling a called terminal according to the present invention.

Mobile terminal i is the terminal identification number of mobile terminal 2
Value where the lower 2 bits of TID2 are masked to "0" (hereinafter "GID
1 ") as the called number, and the terminal identification number TID of the own terminal
#i is the originating number, and the originating signal is sent to the exchange 2 via the base station.
Send to 1.

The exchange 21 sends location information corresponding to GID1.
Obtain from HLR. In the case of FIG. 3, corresponding to GID1, LI1
And LI2. Next, the exchange 21 sends the TID # i to the base station 11 corresponding to LI1 and the base station 12 corresponding to LI2.
Is transmitted, and the base stations 11 and 12 receiving the GID1 call signal transmit the GID1 call signal.

Since the conventional system manages location information for each mobile terminal, only the base station corresponding to one LI sends out a call signal. In the present invention, the base station corresponding to a plurality of LIs is used. Sends a call signal.

FIG. 6 shows a response / connection process when the mobile terminal 1 that has the same GID but is not the destination responds on the receiving side.

The mobile terminal 1 receives the call signal from the base station 11, determines that the mobile terminal 1 belongs to the destination GID1, and enters a response process.

The mobile terminal 1 first obtains a public key PK # i corresponding to the TID # i from the HLR using the call signal TID # i.

Next, using the PK # i as a key, the terminal ID TID1
Is added to the response signal and transmitted. The response signal is transmitted from the base station 11 to the exchange 21 to the base station 11 to the mobile terminal i.
Sent to Here, since the TID1 is encrypted with PK # i, the exchange 21 and the base stations 11 and 12 know the location of the responding mobile terminal, but do not know the TID1. It is difficult to figure out.

The mobile terminal i receives the response signal from the mobile terminal 1, and decrypts TID1 using the secret key SK # i in its own terminal memory.
It determines that the response is from a mobile terminal that is not the destination specified at the time of calling, and stops the process.

FIG. 7 shows a response / connection process when the destination mobile terminal 2 responds on the receiving side.

The mobile terminal 2 receives the call signal from the base station 12, determines that the mobile terminal 2 belongs to the destination GID1, and enters a response process.

The mobile terminal 2 first obtains a public key PK # i corresponding to the TID # i from the HLR using the call signal TID # i.

Next, using the PK # i as a key, the terminal ID TID2
Is added to the response signal and transmitted. The response signal is transmitted from the base station 12 to the exchange 21 to the base station 11 to the mobile terminal i.
Sent to Here, since TID2 is encrypted with PK # i, the location of the responding mobile terminal can be known from the exchange 21 and the base stations 11 and 12, but the TID2 is not known as in the case of the mobile terminal 1. Therefore, it is difficult to grasp the position information of the mobile terminal.

The mobile terminal i receives the response signal from the mobile terminal 2, decrypts the TID2 with the secret key SK # i in its own memory,
The connection request signal is transmitted to the exchange 21 via the base station 11 by judging that the response is the response of the mobile terminal which is the destination specified at the time of calling. This connection request signal can be specified by a temporary identification number such as a call number in the form of a mobile terminal that has returned a response before that, so that the value of TID2 is changed to the exchange 21 and the base stations 11 and 12. You do not need to inform. Therefore, since the exchange 21 and the base stations 11 and 12 do not know the TID2, it is also difficult to grasp the position information of each mobile terminal.

In another embodiment, the bit mask positions of the TID can be arranged at the uppermost position, the middle position, and the position at the top.

Further, the TID is a roaming number, and the HLR is a GLR (Gateway Location Register) or a VLR (Visited Lonel) which plays the role of an HLR for roaming mobile terminals from other networks.
The same configuration is possible during roaming by substituting with a Cation Register.

As described above, the terminal identification number (TID
) Is a terminal group identification number (GID)
The location registration and the call are performed using this terminal group identification number (GID), and the calling terminal selects a mobile terminal to be connected from a plurality of terminals responding to the call, and performs the connection.

According to the present invention, since the information on the position of the user is managed by the terminal group identification number (GID), it is difficult to grasp the position information of each mobile terminal in the network, and the position of the terminal user is difficult. Privacy can be protected.

[0045]

As described above, according to the present invention, information on the position of a mobile terminal (user) is stored in a terminal group identification number (GI).
D), the terminals responding to the call signal encrypt their own terminal identification numbers (TIDs) with the public key of the calling terminal and send them out, and send the terminal identification numbers of the terminals responding to the calling terminal to the secret key. Since it is possible to obtain a terminal identification number by compounding with, the connection terminal can be selected from among them, and it becomes difficult to grasp the position information of each mobile terminal in the network. As a result, privacy regarding the position of the terminal user can be protected.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a mobile communication network.

FIG. 2 Terminal identification number (TID) and terminal group identification number (GID)
FIG.

3A is a diagram illustrating a configuration example inside a home location register, and FIG. 3B is a diagram illustrating a configuration example of an internal memory of a mobile terminal;

FIG. 4 is a diagram showing a location registration process.

FIG. 5 is a diagram showing a calling / calling process.

FIG. 6 is a diagram showing a response / connection process.

FIG. 7 is a diagram showing a response / connection process.

[Explanation of symbols]

 1,2 mobile terminal 11,12 base station 21 exchange

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J104 AA00 JA21 NA02 NA36 NA37 PA01 5K067 AA21 DD17 DD23 DD24 EE02 EE10 EE16 GG01 GG11 HH00 HH05 HH22 HH23 HH24 9A001 BB02 BB03 BB04 CC05 CC07 DD10 EE03 KK56 KK18 JJ18 KK18

Claims (6)

[Claims] 1. A plurality of mobile terminals, and a plurality of base stations wirelessly communicating with the mobile terminals within a service area of the mobile terminals.
In a mobile communication system having an exchange having a call control function to the mobile terminal via these base stations and a home location register having a network database function for managing communication service information for the mobile terminal, A home location register stores a public key table storing a public key corresponding to a terminal identification number indicating each mobile terminal, a terminal group identification number in which the plurality of mobile terminals are grouped, and each mobile terminal belonging to the group. And a location information table in which location information indicating a service area of each base station where the mobile terminal is located is allocated and stored, and the mobile terminal stores the location information to which the mobile terminal belongs and a secret key corresponding to the public key. A memory, wherein the exchange has a public key table and location information of the home location register. Mobile communication system and performs call control to the mobile terminal with reference to Buru. 2. The base station constantly broadcasts location information of its service area. The mobile terminal receives the location information, compares it with its own location information, and registers a location if they do not match. The mobile communication according to claim 1, wherein the home location register receives the location registration signal, rewrites the location information table, and instructs the mobile terminal to rewrite the location information with new location information. system. 3. The mobile terminal on the transmission side transmits its own terminal identification number as a transmission number and a terminal group identification number of a group to which a destination mobile terminal belongs as a reception number. 3. The mobile communication according to claim 1, wherein a call signal is transmitted from a base station corresponding to the location information assigned to the terminal group identification number of the called number by referring to the location information table of the mobile phone. system. 4. The mobile terminal on the receiving side receives the call signal, acquires a public key corresponding to the terminal identification number of the calling number, and encrypts its own terminal identification number with the acquired public key. The mobile terminal on the transmitting side receives the response signal, decodes the terminal identification number encrypted with its own private key, and obtains the terminal identification number on the receiving side. The mobile communication system according to claim 3, wherein 5. The mobile communication system according to claim 1, wherein the terminal group identification number is configured by masking a part of bits constituting the terminal identification number. 6. A mobile terminal roaming from another network,
6. The mobile communication system according to claim 1, further comprising a GLR or a VLR serving as the home location register, wherein a terminal identification number of the mobile terminal is a roaming number.