Patent Publication Number: US-7917158-B2

Title: Method and system for location management and location information providing system

Description:
This application is a continuation of application Ser. No. 10/082,797 filed Feb. 25, 2002 now U.S. Pat. No. 7,574,222, which claims priority under 35 U.S.C. §119 to Japanese Patent Application Nos. JP2001-055819 filed Feb. 28, 2001 and JP2001-110325 filed on Apr. 9, 2001. The entire contents of all of these applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and a wireless communication system for managing information on locations of mobile stations and a location information providing system. 
     2. Description of the Related Art 
     In the conventional mobile communication system, a device for managing location of a plurality of mobile stations is provided, to store information about which area (called “location area”) each of mobile stations is located. When an incoming call directed to a mobile station occurs, the device identifies the location area. Next, the device generates paging signal to transmit to the mobile station via a switch covering the location area and one of the base stations belonging to the switch. 
     In the registration of a location area, firstly a mobile station receives information on location area Secondly, the mobile station transmits a number to identify the mobile station and the location area information, via the base station and the switch. Especially, there is a location management system of a mobile station in a train. In such a system, a communication device is provided in a train, to collectively manage location registration of all mobile stations in the train (reference will be made to Japanese Patent Application No. H11-355835). 
     However, it is cumbersome and costs a lot to provide such device in a train capable of processing requests of location registration from many mobile stations. Even if such devices are introduced, base stations and switches still must process large amounts of request especially in an urban city where many trains run. Specifically, radio channels have to be allocated to exchange signals for location registration between a location registration server and mobile stations. Therefore, radio frequency bandwidth available for voice and data communication is restricted thereby communication traffic volume increases. It is often the case that a moving object such as a train or a bus moves to a place such as a tunnel into which a radio wave transmitted from a base station does not propagate. In this case the base station does not receives any signals either from the object and a mobile station in the object, so that the location server cannot recognize a location of the mobile station. 
     There is a system for providing location information stored in the location server to an external terminal. In such a system, a location of a mobile station can be tracked in real-time. In principle, it is possible to know a future location of a mobile station as long as a user of the mobile station get off a train. However, in the conventional system such information on future location cannot be provided. 
     The present invention, as its object, provides a wireless communication system at a low cost, in which locations of mobile stations moving together with an object such as trans and buses are tracked accurately and efficiently. In addition, the present invention provides a communication system for providing a future location of a mobile station to a third party. 
     To attain the above object, a method of the present invention for managing location information on a mobile station in an object by a server on a mobile network comprising the steps of: 
     upon receiving object identification information from a transmitting device provided in the object, the mobile station transmitting to the server received object identifying information and mobile identifying information for identifying the mobile station; the server receiving and storing correspondingly the object identifying information and the mobile identifying information;
 
obtaining, from a traffic control device which controls movement of the object, object movement information of the object identified by the object identifying information; converting the movement information into a location area information; and
 
managing location of the mobile station on the basis of the location area information.
 
     In this method, a location of mobile station is tracked by transmitting a pair of mobile identifying information and object identifying information. It is not necessary to provide an expensive device, which can deal with registration requests from many mobile stations in an object at one time. It is only an inexpensive device for merely transmitting the object identifying information that is needed. Thus, this system can be established in at low cost. In a preferable embodiment upon receiving a call for the mobile station, the server inquires about the movement information for the traffic control device. In another preferable embodiment the traffic control device notifies the server of the movement information when detecting movement of the object. 
     A method for communication in a communication system of the present invention having a server on a mobile network for communication with a mobile station and a traffic control device for controlling an object comprises the steps of: upon receiving an object identifying information for identifying the object from a transmitting device provided in the object, the mobile station transmitting to the server mobile identifying information for identifying the mobile station and received object identifying information; and 
     the server receiving the mobile identifying information and the object identifying information; 
     storing the mobile identifying information and the object identifying information correspondingly; 
     when receiving a call for the mobile station identified by the mobile identifying information, retrieving the object identifying information corresponding to the mobile identifying information; and 
     transmitting retrieved object identifying information to the traffic control device; and 
     the traffic control device generating movement information on the object identified by the object identifying information; and 
     transmitting generated movement information to the server; and 
     the server converting received movement information into location area information; and 
     paging the mobile station on the basis of the location area information. 
     By using this method, it is not necessary to update registration of location every time a mobile station moves into another location area, once the object identifying information is registered with the server. Therefore, radio traffic according to location registration is reduced. 
     In another embodiment, upon detecting a movement change of the object, the traffic control device generates movement information, transmits to the server the object identifying information and generated movement information. And the server receives the movement information, converts received movement information into location area information about an area within which the mobile station is located and stores the object identifying information and the location area information correspondingly. When receiving a call for the mobile station including the mobile identifying information, the server retrieves the location area information corresponding to the mobile identifying information and pages the mobile station on the basis of the location area information. 
     In this embodiment, the location server keeps the latest location area information on a mobile station. Therefore, the location server does not necessarily request movement information to the traffic control device, when a call for a mobile station is issued. Thus, identifying the mobile station to transmit a paging signal can be done quickly. 
     A communication system of the present invention has a traffic control device for controlling movement of an object and a mobile network. The mobile network comprises a mobile station, a base station for communicating with the mobile station, a switch for communicating with the base station, a location server for communicating with the switch, and an object information server for communicating with the location server and the traffic control device. The mobile station comprises means for receiving object identifying information for identifying the object and transmitting to the base station received object identifying information and mobile identifying information for identifying the mobile station. The location server comprises means for storing the object identifying information and the mobile identifying information correspondingly, both of which sent from the mobile station, means for retrieving and transmitting to the location server the object identifying information corresponding to the mobile identifying information, when receiving from the switch an inquiry of location area information on the mobile station including the mobile identifying information and means for receiving from the object information server and transmitting to the switch the location area information on the object identified by the object identifying information. The object information server comprises means for receiving from the location server and transmitting to the traffic control device the object identifying information, means for receiving from the traffic control device movement information on the object identified by the object identifying information, means for converting received movement information into the location area information and means for transmitting converted location area information to the location server. The traffic control device comprises means for receiving from the object information server the object identifying information and generating the movement information on the basis of received object identifying information and means for transmitting generated movement information to the object information sever. 
     In a preferable embodiment, the traffic control device comprises means for detecting movement change of the object and generating movement information representing movement of the object and means for transmitting to the object information server the object identifying information and the movement information. The object information server comprises means for receiving from the traffic control device the object identifying information and the movement information and converting received movement information into location area information representing an area within which the mobile station is located and means for transmitting to the location server the object identifying information and the location area information. The location server comprises a first storing means for receiving from the object information server and storing correspondingly the object identifying information and the location area information, a second storing means for storing correspondingly the object identifying information and the mobile identifying information, both of which sent from the mobile station and means for retrieving from the second storing means the object identifying information corresponding to the mobile identifying information, when receiving from the switch an inquiry of the location area information including the mobile identifying information. 
     Furthermore, it is possible that when not receiving from the transmitting device the object identifying information and moving into another location area, the mobile station transmits to the location server updated location information on the mobile station and the mobile identifying information. In addition, when receiving the location area information and the mobile identifying information sent from the mobile station, the location server stores to the second storing means the mobile identifying information and the updated location area information correspondingly, instead of the object identifying information. 
     An information providing system of the present invention for providing location information on a mobile station in a mobile network to a terminal comprises a location server in the mobile network for managing location of the mobile station and a location information server for carrying out communication with the terminal. Upon receiving from a transmitting device provided in an object identifying information for identifying an object, the mobile station transmits to the location server the mobile identifying information for identifying the mobile station and received object identifying information. The location server receives and stores correspondingly the object identifying information and the mobile identifying information sent from the mobile station. Upon receiving from the terminal an inquiry of location information on the mobile station including the mobile identifying information, the location information server judges whether the object identifying information corresponding to the mobile identifying information is stored in the location server. If the object identifying information is stored, transmits to the terminal boarding information representing that the mobile station is in the object. By using the terminal in this system, a person can know that the mobile station is in the object. 
     In a preferable embodiment, the location information server further comprises means for identifying the mobile station using the mobile identifying information, carrying out communication with the mobile station, and obtaining from the mobile station the location information and transmitting to the terminal the boarding information and the location information. 
     In another preferable embodiment, the information providing system further comprises an object information server for carrying out communication with a traffic control device which controls movement of the object. Upon receiving from the terminal an inquiry of location information including the mobile identifying information, the location information server transmits the mobile identifying information to the location server. Also, upon obtaining from the location server the location information, the location information server transmits to the terminal the boarding information and the location information. Upon receiving from the location information server the mobile identifying information, the location server transmits to the object information server the object identifying information corresponding to the mobile identifying information. Upon receiving the object identifying information from the location server, the object information server obtains from the traffic control device the movement information on the object corresponding to the object identifying information, converts obtained movement information into the location information, and transmits the location information to the location information server via the location server. 
     It is possible that when receiving from the terminal an inquiry of the location information on the mobile station, the location information server generates, on the basis of the movement information, estimated location information representing a future location on the mobile station and transmits the estimated location information to the terminal. In this system a person can obtain a future location of a mobile station in addition to the present location. 
     In another preferable embodiment, the object information server stores the movement information obtained from the traffic control device and the object identifying information correspondingly. When receiving from the location server the object identifying information, the object information server generates the location information on the object identified by the object identifying information on the basis of stored movement information on the object. 
     It is possible that upon detecting a movement change of the object, the traffic control device updates and notifies to the object information server of the movement information. Also, the object information server receives the movement information and generates the location information on the basis the movement information. 
     A method of the present invention for providing location information of a mobile station in a mobile network to a terminal comprises the steps of: 
     the mobile station receiving, from a transmitting device provided in an object, object identifying information for identifying the object; transmitting to a server in the mobile network the object identifying information and mobile identifying information for identifying the mobile station;
 
the server storing the object identifying information and the mobile identifying information correspondingly;
 
when receiving from the terminal an inquiry of location information on the mobile station including the mobile identifying information, judging whether the object identifying information corresponding to the mobile identifying information is stored in the server; and
 
if the object identifying information is stored, generating and transmitting to the terminal boarding information representing that the mobile station is in the object.
 
     In a preferable embodiment, the server stores the object identifying information and the mobile identifying information correspondingly. When receiving from the terminal an inquiry of location information on the mobile station including the mobile identifying information, the server retrieves the object identifying information corresponding to the mobile identifying information, obtains movement information on the object identified by the object identifying information, converts obtained movement information into the location information and transmits the location information to the terminal. 
     It is possible that when receiving the movement information, the server generates, on the basis of the movement information, estimated location information representing a future location of the mobile station and transmits the estimated location information to the terminal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is shows a communication system based on the first embodiment 
         FIG. 2  is a schematic diagram of a location server in the system. 
         FIG. 3  shows a detail of a location table in the system. 
         FIG. 4  is a schematic diagram of an object information server in the system. 
         FIG. 5  is a sequence diagram of the system. 
         FIG. 6  is a schematic diagram of an object information server used for a communication system based on the second embodiment. 
         FIG. 7  shows details of a first and a second location table of the location server. 
         FIG. 8  is a sequence diagram of the system based on the second embodiment. 
         FIG. 9  is an information providing system based on the third embodiment. 
         FIG. 10  is a schematic diagram of an information server in the system. 
         FIG. 11  is schematic diagram of a mobile station. 
         FIG. 12  is a sequence diagram of the system. 
         FIG. 13  is a schematic diagram of an object management device in an information providing system based on the fourth embodiment. 
         FIG. 14  shows a detail of a management table of the object information server. 
         FIG. 15  is a sequence diagram of the information providing system based on the fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. 
     1. First Embodiment 
     1-1. Configuration of a Communication System of First Embodiment 
       FIG. 1  illustrates a wireless communication system based on the first embodiment of the invention. As shown in  FIG. 1 , the system comprises a mobile network NET, a moving object  2 , and a traffic control device  30 . 
     Object  2  is, for example, a train, a bus, and other means of transportation. It will now be described assuming that Moving object is a train. In the figure only a moving object  2  is illustrated but in actuality, many trains  2  exist in the system. Traffic control device  30  manages movements of the trains. Traffic controls device  30  keeps track of each train, specifically, has present location, train schedule, and other information related to the train such as delay. Also, Traffic control device  30  generates movement information INFx, which is the latest information on a movement of an object, to transmit other devices. 
     Movement information INFx includes object location information INF 1  on a location of Object  2  and related information INF 2  for the movement. Specifically, a form of location information INF 1  takes a form of “Longitude, Latitude” or “Name of line, Distance from neighboring station, Direction”. For example, the detail of Location information INF 1  is “Long. 136° 15′ E., 35° 45′ N.”, or “Tokaido line, 2 km from Shinagawa, to Yokohama”. Related information INF 2  includes a name of a train such as “Hikari No. 10” and a delay or suspension. 
     Mobile communication network NET has a plurality of base stations  3 - 1 ,  3 - 2 , . . . ; a plurality of switches  4 - 1 , 4 - 2 , . . . ; object information server  40 A; and location server  50 A. Location server  50 A manages location area information of all mobile stations it covers. 
     Each of base stations  3 - 1 ,  3 - 2 , . . . is provided at a certain distance from neighboring one and covers a base station areas  4   s  each lettered “ 4   a ” through “ 4   f ” as shown in  FIG. 1 . In other words, each of base stations can carry out radio communication with mobile stations within one of base station areas  4  it covers. As shown, each of base stations  3 - 1  through  3 - 6  covers each of Base station areas  4   a  through  4   f . Each Location area  5  lettered  5 A and  5 B is a compilation of base station areas  4   s . Each of Switches  4 - 1 , 4 - 2 , . . . covers one of Location areas  4 . 
     Object  2  has a transmitting device TD and moves on a railroad L. Railroad L extends across boundaries of Location areas  5 . Transmitting device transmits an object ID number IDt by radio. Each of Objects  2  has a unique object ID number IDt. Each of Mobile stations  1  stores a unique mobile ID number IDm to identify a mobile station uniquely. Mobile ID number is, for example, a phone number. 
     When a user of Mobile station  1  is not in a train, Mobile station  1  receives and stores Location area information INF from Base station  3 . When Mobile station  1  moves into another Location area  1 , Mobile station  1  notifies Location information INF and Mobile ID number IDm to mobile communication network NET via Base station  3 . When a user of Mobile station  1  gets aboard Object  2 , Mobile station  1  receives Object ID number IDt from Transmitting device TD and notifies Mobile ID number IDm and received Object ID number IDt to mobile communication network NET via Base station  3 . 
     Specifically, Mobile station  1  keeps watching on reception of Object ID number IDt. Only when Mobile station receives Object ID number IDt, Mobile ID number IDm and Object ID number IDt are transmitted to Mobile communication network NET. In other words, Location area information INF is not transmitted during the ride. This results in a reduction of frequency of transmission of information on location about a mobile station that is necessary for a registration. 
     1-2. Configuration of Location Server  50 A 
     As shown in  FIG. 2 , Location server  50 A has a control unit  51  and a location table TBL. Control unit  51  reads from or writes to Location table TBL data. In addition, Control unit  51  carries out communication with Object information server  40 A and Switch  4 , to manage locations of all Mobile stations  1  in Mobile communication network NET. In addition, Location server  50 A generates paging signal when an incoming call for Mobile station  1  is issued. 
       FIG. 3  shows information stored in Location table TBL. Location table TBL has a plurality of records Rb 1 , Rb 2 , . . . , in each of which a Mobile ID number IDm and location information of a mobile station are stored. The location information is either Location information INF or an Object ID number. Specifically, when a Mobile station  1  is in a train Object ID number IDt is stored, while when not in a train Location area information INF is stored. 
     For example, if a mobile station whose Mobile ID number IDm is “X0001”, is in Object  2  whose Object ID number is “A01234”, “X00001” and “A01234” are stored in Rb 1  of Location table TBL correspondingly as shown in  FIG. 3 . If a mobile station whose Mobile ID number is “X0003” is not in Object  2 , Mobile ID number “X00003” and Location area information INF “5B” are stored correspondingly in a record Rb 3 . 
     1-3. Configuration of Object Information Server  40 A 
       FIG. 4  is a schematic diagram of Object information server  40 A. As shown, Location information server has a control unit  41  and a convert unit  42 . Control unit  41  carries out communication with Traffic control device  30  and Location server  50 A as well serves as nerve center of Object information server  40 A. Convert unit  42  converts Object location information INF 1  included in Movement information INFx sent from Traffic control device  30  into Location area information INF. 
     In one example, Convert unit  42  has a first table for storing Location area information INF and locations represented by latitude and longitude correspondingly, and a second table for information on routes of trains and Location area information INF. Upon obtaining Movement information INF 1  in a “Latitude, Longitude” form, Convert unit  42  retrieves from the first table Location area and outputs to Control unit  41  information corresponding to object location information INF. In case of reception of Movement information INF 1  in a “Line name, Distance from neighboring station, Direction” form, Convert unit  42  retrieves from the second table and outputs to Control unit  41  a present location of Object  2  corresponding to the Object location information INF 1 . 
     It is noted that although Object location information INF 1  could take various forms, conversion of any types of Location area information INF 1  can be effected by Convert unit  42 . 
     1-4. Operation of the System 
     One example of operations of a wireless communication system of the invention will now be described referring to the drawings.  FIG. 5  is a sequence diagram of the communication system. When Mobile station  1  comes into Object  2 , the Mobile station  1  receives an Object ID number IDt sent from Transmitting device TD (step S 1 ) and transmits to Location server  50 A registration request including the Object ID number IDt and a Mobile ID number IDm via Base station  3  and Switch  4  (not shown) (step S 2 ). When Location server  50 A receives the registration request, the Object ID number IDt and the Mobile ID number IDm are extracted from the request and stored in Location table TBL (step S 3 ). 
     For example, if the Mobile ID number IDm is “X0002” and the Object ID number is “A01234”, “X0002” and “A01234” are stored correspondingly in Rb 2  of Location table TBL as shown in  FIG. 3 . 
     It is noted that even when a Mobile station  1  comes across a border between location areas, the Mobile station  1  does not transmit Location area information as long as the Mobile station  1  is in an object thereby keeps receiving Object ID number IDt. 
     When one of Switches  4  receives a call for Mobile station  1 , the Switch  4  issues a location request REQ 1  to Location server  50 A (step S 4 ). REQ 1  includes Mobile ID number IDm of the Mobile station  1 . When Location server receives Location request REQ 1 , Control unit  51  retrieves from Location table location information corresponding to the Mobile ID number (step S 5 ). Control unit  51  judges whether received location information is Location area information INF or Object ID number IDt. 
     If Control unit  51  retrieves Location information INF, Control unit  51  transmits retrieved Location information INF to the Switch  4 . In this case, Location server  50 A generates and transmits to Object information server  40 A location request REQ 2  (step  6 ). 
     Object information server  40 A generates and transmits to Traffic control device  30  a movement request REQ 3  including the Object ID number IDt (step S 7 ). Traffic control device  30  firstly converts received Object ID number IDt into a certain number available for Traffic device  30  and secondly generates Movement information INFx. Net, Traffic control device  30  transmits Movement response RES 3  including the Object ID number IDt and the Movement information INFx to Object information server  40 A (step S 8 ). 
     Object information server firstly  40 A converts Object location information INF 1  included in received Movement information INFx into Location area information INF (step S 9 ) and next transmits a location area response RES 2  including the location area information INF and the Object ID number IDt to Location server  50 A (step S 10 ). 
     After the reception of Location area response RES 2 , Location server  50 A transmits to Switch  4  a location area response RES 1  including the location area information INF and the Object ID number IDt (step S 11 ). Switch  4  issues a paging request including the Mobile ID number to Base stations  3  within a location area designated by the Location area information INF. When the Mobile station answers, the connection is established. 
     In this system a mobile station does not notify location area information to any nodes in a mobile network during the ride. Therefore, the load on the network is reduced thereby improves system performance. 
     In addition, a communication device capable of registering many mobile stations in a train at one time is not necessarily introduced. The only device provided in a train is one for transmitting an ID number by radio. Therefore, this system can be established at a low cost. In addition, since Convert unit is introduced to convert Movement information INFx into Location area information INF, information on location of a train can be managed regardless of data format of object location information which a traffic control device has. 
     2. Second Embodiment 
     2-1. Configuration of a Communication System 
     A wireless communication system based on the second embodiment is similar to that of the first embodiment, except that a location server  50 B is introduced instead of Location server  50 A. 
       FIG. 6  is a schematic block diagram of Location server  50 B. As shown, Location server  50 B has a control unit  51 , first location table TBL 1 , and second location table TBL 2 . Second location table TBL 2  is the same as Location table of the first embodiment  FIG. 7  shows details of the First location table and Second location table. First location table TBL 1  has a plurality of records Ra 1 , Ra 2 , . . . , each storing Object ID number IDt and location area information INF correspondingly. It is noted that the records and Objects  2  are same in number. For example, if Object  2  is located within a location area  5 A and Object ID number IDt is “A01234”, “A01234” and “ 5 A” are stored in a record Ra 1  of First location table TBL 1  as shown in  FIG. 7 . 
     In this system upon updating movement information INFx on an Object  2 , Traffic control device  30  transmits the updated information to Object information server  40 A. Object information server  40 A firstly converts received information INFx into Location area information INF and secondly transmits the converted information INF to Location server  50 B. Location server  50 B receives and stores to First location table TBL 1  the Movement information INFx. In this way information stored in First location table TBL 1  is updated. Information stored in Second location table TBL 2  is updated by notification from Mobile station  1 , as described in the first embodiment. 
     2-2. Operation of the System 
     Operations of the wireless communication system based on the second embodiment will now be described referring to  FIG. 8 . As shown, steps S 1  through S 3  are the same as those of first embodiment. 
     When Traffic control device  30  updates Movement information INFx, Traffic control device  30  transmits a movement notice N 1  including an Object ID number and updated information INFx to Object information server  40 A (step S 21 ). When receiving Movement notice N 1 , Object information server  40 A converts Object location information INF 1  included in the Movement information INFx into Location area information INF (step S 22 ). Next Object information server  40 A generates and transmits to Location server  50 B an Area notice N 2  (step S 23 ). 
     Suppose here that Object  2  is “Tokaido Line” moving from Shinagawa station to Yokohama station and Shinagawa and Yokohama station are located within “ 5 A” and “ 5 B”, respectively. When the train arrives at Yokohama station, Traffic control device  30  generates Object location information INF 1  indicating a stop of the tram at Yokohama station. Next, Traffic control device  30  transmits Movement notice N 1  including the information INF 1 . Object information server  40 A receives Movement notice N 1 . Convert unit  42  converts INF 1  into Location area information INF. Control unit  41  generates and transmits to Location server  50 B Area notice N 2  including an Object ID number IDt and the location area information INF. 
     Location server  50 B receives the Area notice N 2  and updates location area information INF corresponding to the Object ID number IDt stored in First location table TBL 1  (step S 24 ). Specifically, if Object ID number IDt is “A01234”, Location area information INF in record Ra 1  is updated from “ 5 A” to “ 5 B” shown in  FIG. 7 . In this way First table TBL 1  has the latest information on movement. 
     In other words, Object information server  40 A does not ask Traffic control device for movement information when a call for Mobile station  1  in Object  2  is issued. Therefore, Location server  50 B is able to obtain location area information on the mobile station quickly, thereby Switch  4  is able to route incoming calls effectively. 
     3. Third Embodiment 
     An information providing system based on the third embodiment is an application of the system based on the second embodiment. 
     3-1. Configuration of the System 
       FIG. 9  is a schematic diagram of the system of this embodiment. This system differs from that of the second embodiment only in having a Location information server  60 , Client terminal  70 , and Mobile station  1 A instead of Mobile station  1 . Client terminal  70  is, for example, a Personal Computer (PC), Personal Digital Assistants (PDA), mobile phone, and other communication devices, which carry out communication with Location information server  60 . 
       FIG. 10  is a schematic block diagram of Location information server  60 . As shown, Location server has a Central Processing Unit (CPU)  61 , Read Only Memory (ROM)  62 , Random Access Memory (ROM)  63 , Interface  64 , and Hard disk  65 . Location information server  60  provides location information of Mobile station  1 A responsive to a request from Client terminal  70 . 
     Specifically, CPU 61  controls all the functions of all devices in Location information server  60  and executes applications. ROM 62  stores, for example, a boot program. RAM  63  temporarily stores data or application programs for CPU 61 . Hard disk  65  stores application programs, which are a communication program for the communication with Client terminal  70  and Location server  50 B, an estimation program for the estimation of a future location of Object  2 , and a call program for calling Mobile station  1  on the basis of Location area information INF. Bus  150  links all devices. 
     Mobile station  1 A differs form Mobile station  1  in having functions of generation and transmittance of location information.  FIG. 11  is a schematic diagram of Mobile station  1 A. As shown, Mobile station  1 A has a control unit  100 , Global Positioning Systems (GPS) receiver  110 , radio device  120 , input device  130 , Liquid Crystal Display (LCD)  140 , and Bus  150 . GPS receiver  110  receives radio wave sent by a satellite and generates information on the present location of Mobile station  1 A including the longitude and latitude. Radio device  120  carries out radio communication with Base station  3  under control of CPU 61 . Input device  130  has buttons including Push Button (PB) and cursor keys and sends information on a user&#39;s direction into Control unit  100 . LCD  140  displays information. Control unit  100  has a CPU  111 , ROM  112 , RAM  113 , and EEPROM  114 ; and controls all the functions of all devices in Mobile station  1 A. ROM  112  has application programs for the control of devices, communication with Location information server  60 , and generation of related information. 
     The related information includes, for example, a direction and velocity of Object  2 . RAM  113  temporarily stores data and application programs for CPU  111 . EEPROM  114  nonvolatile memory and stores updated application programs. Bus  150  electrically connects all devices. 
     3-2. Operation of the System 
       FIG. 12  is a sequence diagram of the information providing system. It is noted that this system carries out procedures for updating location area information INF, which is the same as that in the second embodiment. 
     A user operates Client terminal  70  with Input device  130  to access Location information server  60 . Client terminal  70  displays in LCD  140  direction for input of Mobile II) number. When the user input a Mobile ID number IDm (phone number, for example), Client terminal  70  transmits to Location information server  60  location request REQ  4  including the Mobile ID number IDm (step S 31 ). 
     Upon receiving location request REQ  4 , Location information server  60  transmits location request REQ  5  including the Mobile ID number to Location server  50 B (step S 32 ). Location server  50 B receives location request REQ 5  and retrieves location area information INF corresponding to the Mobile ID number IDm from First location table TBL 1  and Second location table TBL 2  (step S 33 ). Furthermore, if Object ID number IDt is stored in Second Location table TBL 2 , Location server set a flag FLG to “1”. If Object ID number IDt is not stored, the flag FLG is set to “0” (step S 33 ). 
     Next, Location server  50  transmits to Location information server  60  a location request RES  5  including the Location area information INF and Flag FLG (step S 34 ). Location information server  60  receives Location response RES  5  and executes the estimation program, to page Mobile station  1 A (step S 35 ). Specifically, Location information server pages, via a Switch, Base stations  3  located within an area identified by the Location area information INF, by sending a paging signal including Mobile ID number. In addition, if Flag FLG is set to “1”, Location information server  60  generates boarding information indicating whether a user of Mobile station  1 A takes on a train. If Flag FLG is set to “0”, the boarding information is not generated. 
     Upon receiving the paging signal, Mobile station  1 A generates and transmits to Location information server  60  location information on the present location and related information including a direction and velocity (step S 36 ). 
     Location information server  60  receives the location information and the related information from Mobile station  1 A and transmits the location information, related information, and the boarding information to Client terminal  70  (step  37 ). For example, a user of a mobile station  1 A aboard a train which is located at Long. 136° 15′ E., 35° 45′ N. and heading toward South at a velocity of 46 Kilometers/hour. In this case, Location information “Long. 136° 15′ E., 35° 45′ N.”, related information “46Km/h South”, and boarding information “Now boarding” are transmitted to Client terminal  70 . 
     In case a user is not aboard, Location information server  60  does not transmit the boarding information since Flag FLG in location response RES  5  is set to “0”. As described above, people are able to obtain boarding information as well as location information of Mobile station  1 A by operating Client terminal  70  in this system. 
     3-3. Modification of the Third Embodiment 
     As described above, the system of the third embodiment is comprised by adding the system of the second embodiment to Location server  60  and Client terminal  70 . However, it is possible to introduce a system in which Location server and Client terminal  70  are added to the system of the first embodiment. 
     In this system, when Location server  50 A receives Location request REQ  5  from Location information server  60 , steps S 5  trough S 10  shown in  FIG. 5  are carried out. In this way Location server  50 A obtains and transmits to Location information server  60  Location area information INF. Next, Location information server  60  pages Mobile station  1 A, on the basis of the Location area information INF, similarly to the third embodiment. 
     4. Fourth Embodiment 
     4-1. Configuration of a System 
     An information providing system based on the fourth embodiment is the same as that of the third embodiment except for detailed function of Traffic control device  30  and use of an object information server  40 B instead of  40 A and Mobile station  1  instead of  1 A. Specifically, Traffic control device  30  transmits Movement information INFx only when receiving a request from Object information server  40 B, similarly to the first embodiment. Object information server  40 B has a management table TBLk as shown in  FIG. 13 , differing from Object information server  40 A. 
       FIG. 14  shows an example of information stored in Management table TBLk. Management table TBLk has a plurality of records Rc 1 , Rc 2 , . . . , each storing an Object ID number IDt, Movement information INFx, and timestamp T. Timestamp T represents the time when Movement information INFx is stored. Specifically, upon storing Movement information INFx, Control unit  51  obtains time from a timer not shown in the figure and writes the time to Management table TBLk. For one example, Record Rc 1  indicates that Object location information INF 1  “Long. 136° 15′ E., 35° 45′ N.” is stored corresponding to Object ID number “A01234” at 13:00. 
     4-2. Operations of the System 
     Operations of the system will now be described referring to  FIG. 15 .  FIG. 15  is a sequence diagram of the system. Steps S 41  and S 42  is the same as steps S 31  and S 32  as described above, respectively. 
     Next, Location server  50 B accesses Second location table TBL 2 . If Object ID number IDt is stored corresponding to a Mobile ID number, Location sever  50 B sets the flag FLG to “1”. If the Object ID number is not stored, FLG is set to “0” (step S 43 ). If Object ID number IDt is stored, Location server  50 B transmits movement request REQ  8  including the Object ID number IDt to Object information server  40 B (step S 44 ). 
     Object information server  40 B receives the Movement request REQ  8  and retrieves from Management table TBLk Movement information INFx and Timestamp T, each corresponding to the Object ID number IDt. If Movement information INFx is not stored in Management table TBLk or a predetermined time has elapsed since the time represented by Timestamp T, Object information server  40 B transmits a movement request REQ  9  to Traffic control device  30  (step S 45 ). 
     Traffic control device  30  generates Movement information INFx about an Object  2  identified by the received Object ID number IDt and transmits to Object information server  40 B a movement response RES  9  including the INFx (step S 47 ). Object information server  40 B transmits to Location server  50 B a movement response RES  8  including the Movement information INFx (step S 48 ). 
     If Movement information INFx is stored in Management table TBLk and a predetermined time has not elapsed since time T, Object information server  40 B skips steps S 45  through S 47  and transmits a movement response RES  8  to Location server  50 B (step S 48 ). 
     Location server  50 B transmits a movement response RES  7  including the Movement information INFx to Location information server  60  (step S 49 ). Location information server  60  receives Movement response RES 7  and extracts INF 2  from the Movement information INFx included in Movement response RES  7  to estimate a future location of Object  2 . A specific way of estimation is as follows: 
     Suppose that a user of a mobile station  1  is in a train whose Object ID number is “A01234” and Management table TBLk stores detailed information shown in  FIG. 14 . When Location information server  60  receives a location request REQ 6  from Client terminal  70 , steps S 42  through S 49  are carried out as described above. As a result, Location information server  60  obtains Related information INF 2  “Azusa No. 2”. Next, Location information server  60  estimates a future location of the train referring to timetable data stored in Hard disk  65 . The estimated location information generated by Location information server  60  includes, for example, “arrive at Kofu in 18 minutes”. 
     Next Location information server  60  transmits to Client terminal  70  a location response RES 6  including Object location information INF 1 , Related information INF 2 , and Boarding information (step S 50 ). Specifically, INF 1  “Long. 136° 15′ E., 35° 45′ N.”, INF 2  “Azusa No. 2”, and Estimated location information “This train will arrive at Kofu in 18 minutes”, and Boarding information “Now boarding” is transmitted to Client terminal  70 . 
     As described in this embodiment, a person is able to obtain the present and future location of a mobile station by inputting a Mobile ID number to Client terminal  70 . In this system, location information of a Mobile station can be obtained, even if the mobile station in Object  2  cannot carry out radio communication with Base stations because Object  2  is moving through a tunnel, for example. 
     In addition, the number of inquires to Traffic control device  30  for getting the latest information on an object can be minimized. Since Object information sever  40 B checks Timestamp T, to judge whether to obtain the information from Traffic control device  30 . In other words, the information is obtained efficiently and precisely. 
     4-3. Modification of the Fourth Embodiment 
     It is possible that Traffic control device  30  transmits the latest Movement information INFx to Movement information server  40 B every time the information INFx is updated. In this case, Location server is able to obtain the latest information on Object  2  and needs not to refer to Timestamp T. 
     It is also possible that a person uses Client terminal  70 , to designate the detailed future location of a Mobile station. For example, a user inputs the desired time (an hour later, for example) in addition to Mobile ID number. After reception of Object location information INF 1 , Related information INF 2 , and Estimated location information, the Location information server  60  retrieves the estimated location of “Azusa No. 2” (near Matsumoto station, for example) referring to the schedule stored Hard disk  65 . Retrieved information is transmitted to Client terminal  70 . 
     5. Supplement 
     As described in the above embodiments, when a user of Mobile station  1  gets aboard a train, Mobile station  1  receives Mobile ID number IDm from Transmitting device TD and notifies Mobile ID number IDm and received Object ID number IDt to Mobile communication network NET via Base station  3 . However, it is possible that a device provided in Object  2  transmits Mobile ID numbers IDms each of which is sent from Mobile station  1  and Object ID number IDt, to mobile communication network NET. In this case, the device has the function of receiving Object ID number IDt and Mobile ID number IDm. As an example, Transmitting device TD may have the function. The point is that Object ID number IDt and Mobile ID number IDm are transmitted together to Mobile communication network NET, when a user gets aboard. 
     Although the foregoing description provides many variations for use of the present invention, these enabling details should not be construed as limiting in any way the scope of the invention, and it will be readily understood that the present invention is susceptible to many modifications, and equivalent implementations without departing from this scope and without diminishing its attendant advantages. It is therefore intended that the present invention is not limited to the disclosed embodiments but should be defined in accordance with claims which follow.