Abstract:
A wireless communication system provides a decryption module for decrypting card information on a roadside unit for information registration and a roadside unit for toll collection instead of providing the decryption module on a vehicle unit. In this manner, the wireless communication system can accommodate an IC card that uses a new encryption method more easily relative to a conventional wireless communication system, because the roadside units are smaller in number in comparison to the vehicle units at the time of system operation with greater allowance for demand for space efficiency and cost reduction.

Description:
CROSSREFERENCE TO RELATED APPLICATION 
       [0001]    This application is based on and claims the benefit of priority of Japanese Patent Applications No. 2006-240491 filed on Sep. 5, 2006, and No. 2006-313377 filed on Nov. 20, 2006, the disclosure of which is incorporated herein by reference. 
       FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure generally relates to a wireless communication system and apparatus for wirelessly collecting a toll. 
       BACKGROUND INFORMATION 
       [0003]    An ETC system (the Electronic Toll Collection System) is known as one of the wireless communication systems performing receipt such as a toll through radio. This ETC system is the system which automatically performs toll payment by employing a wireless communication between a roadside unit at a toll gate and a vehicle unit on a vehicle, thereby allowing the vehicle to pass through the toll gate without stopping. 
         [0004]    As for the ETC system, the vehicle unit of the system is currently in the course of utilization for payment in a fast food shop, of parking fee in an amusement park or the like, and a wide variety of implementations is now being expected. 
         [0005]      FIG. 17A  is a block diagram showing a constitution example of an in-vehicle unit in a conventional ETC system. The in-vehicle unit  160  equips a DSRC unit  162 , an HMI  163 , an ETC-SAM  164  and an integrated circuit (IC) card interface  165  as well as a control unit  166  having a radio antenna  161  as shown in the figure. In this case, “SAM” generally stands for Secure Application Module in the art. 
         [0006]    A radio antenna  161  is an antenna for Dedicated Short Range Communication. The DSRC unit  162  performs transmission and reception of information by DSRC through the radio antenna  161 . 
         [0007]    The HMI  163  is a unit offering an interface (i.e., Human Machine Interface) for communication between a human being and a device. More practically, the HMI  163  is constituted from an operation button, LEDs and the like. 
         [0008]    The ETC-SAM  164  equips a vehicle unit v-SAM  164   a  for the in-vehicle device and a card v-SAM  164   b  for the IC card. The vehicle unit v-SAM  164   a  for the in-vehicle device performs encrypting/decrypting (e.g., encryption/decryption) of information communication with the roadside device as well as encrypting/decrypting of vehicle device information (a management number, a form registration number, the number of a vehicle and the like). On the other hand, the v-SAM  164   b  for IC card performs encrypting/decrypting of card information (a card number, expiration date, name information, a card issuer number, a card type, money balance, use history information and the like). 
         [0009]    The IC card interface  165  is an interface to perform communication with the IC card  167 , and the is used to read out stored information of the IC card  167 . In this case, the IC card interface  165  is controlled by the v-SAM  164   b.    
         [0010]    The control unit  166  consists of a central processing unit, a ROM, a RAM, an I/O and the like, and controls the DSRC unit  162 , the HMI  163  and the ETC-SAM  164  in a unified manner. 
         [0011]      FIG. 17B  is a block diagram showing a constitution example of a roadside unit in the conventional ETC system. The roadside unit  180  equips a DSRC unit  182 , a road SAM  183 , a communication interface (I/F)  184  and a control part  185  with a radio antenna  181  as shown in the figure. 
         [0012]    The radio antenna  181  is an antenna for use in DSRC. The DSRC unit  182  performs transmission and reception of information by DSRC through the radio antenna  181 . 
         [0013]    The road SAM  183  is a unit having function of decrypting encrypted information sent from the in-vehicle unit  160  and function of encrypting information to be sent to the in-vehicle unit  160 . 
         [0014]    The communication interface  184  is a wired interface to communicate with an information center or a toll gate computer. In this case, the information center is a computer having function to manage the whole ETC system, and the toll gate computer is a computer having function to perform a process for toll collection. 
         [0015]    The control unit  185  consists of a central processing unit (CPU), a ROM, a RAM, an I/O and the like, and controls the DSRC unit  182 , the road SAM  183  and the communication interface  184  in a unified manner. 
         [0016]      FIG. 18  is a sequence chart showing an example of a data processing sequence between the in-vehicle device  160  (the control unit  166 , the ETC-SAM  164 ), the roadside unit  180  and the IC card in the conventional ETC system. 
         [0017]    When the IC card  167  is set to the in-vehicle device  160 ; the control unit  166  sends to ETC-SAM  164  a card information read request (S 905 ). Upon receiving the card information read request on the ETC-SAM  164 , the card v-SAM 164   b  sends to the IC card a card information retrieval request through the IC card interface  165  (S 906 ), and retrieves the encrypted card information from the IC card (S 910 ). Then, the card v-SAM 164   b  decrypts the encrypted card information to pass it to the control unit  166  (S 915 ). 
         [0018]    The control unit  166  stores the decrypted card information after reception of the information, and performs communication with the roadside equipment  180  as long as the IC card is set in the vehicle unit  160 . 
         [0019]    Then, as the encrypted information is passed from the roadside unit  180  to the vehicle unit  160  (S 620 ), the control unit  166  in the vehicle unit  160  passes the information to the ETC-SAM  164  for decryption (S 925 ). 
         [0020]    As the ETC-SAM  164  receives the encrypted information, the ETC-SAM  164  decrypts the information with the vehicle unit v-SAM  164   a , and passes it to the control unit  166  (S 930 ). Then, the control unit  166  receives the decrypted information, and executes a predetermined process that utilizes the received information. 
         [0021]    Further, when the control unit  166  of the in-vehicle unit  160  is required to send the card information and the like in the storage to the roadside equipment  180  after encryption, the control unit  166  passes the information to the ETC-SAM  164  for encryption (S 935 ). 
         [0022]    The ETC-SAM  164  encrypts the received information with the vehicle unit v-SAM  164   a  upon receiving the information, and passes it to the control unit  166  (S 940 ). 
         [0023]    The control part  166  transmits the encrypted information to the roadside unit  180  upon receiving the information (S 945 ). The above-described encryption/decryption scheme is disclosed in Japanese Patent Laid-Open No. JP-A-2004-62468 (This document is also published as US patent document U.S. Pat. No. 6,920,379). 
         [0024]    As described above, the encrypted card information retrieved from the IC card is used after decryption with the card v-SAM 164   b  in the ETC-SAM  164  in the conventional ETC system. In other words, the card v-SAM 164   b  is indispensable to the in-vehicle unit  160 . 
         [0025]    Therefore, in dealing with an application that is different from the ETC system, the in-vehicle unit is required to have a different module that is equivalent to the vehicle v-SAM 164   b  when the application uses a different encryption method to communicates with an IC card. 
         [0026]    The above-described situation becomes a problem when various applications are realized in the ETC system. In other words, the in-vehicle unit increases its volume and complicates its structure as well as increasing the difficulty of adding applications after distribution of the in-vehicle unit in the market if different modules are added thereon. 
         [0027]    Further, because the IC card is required to be inserted in the in-vehicle unit when the in-vehicle unit communicates with the roadside unit, the user is obliged to re-insert the IC card in the in-vehicle unit after pulling the IC card at, for example, a service area in an expressway or the like if the toll is collected at an exit from the expressway. 
       SUMMARY OF THE DISCLOSURE 
       [0028]    In view of the above and other problems, the present disclosure provides a wireless communication system that is convenient for a user of a vehicle unit and a system administrator. 
         [0029]    The wireless communication system in the present disclosure includes a vehicle side controller that transmits encrypted information retrieved from an external memory medium (e.g., an IC card, a memory card or the like) through an interface unit to a first roadside unit through a vehicle side wireless communication unit, and a controller in the first roadside unit transmits the encrypted information that is received from the vehicle unit through the wireless communication unit in the first roadside unit back to the vehicle unit through the wireless communication unit in the first roadside unit after verifying authenticity of a content of the encrypted information by decrypting it with a security unit in the first roadside unit. 
         [0030]    Then, the controller in the vehicle unit stores in a memory unit the encrypted information that is received from the first roadside unit through the vehicle side wireless communication unit, and the controller in the vehicle unit transmits the encrypted information that is stored in the memory unit through the vehicle side wireless communication unit to a second roadside unit thereafter upon having a transmission request for the encrypted information that is stored in the external memory medium from the second roadside unit. Then, a controller in the second roadside unit puts the encrypted information that is received by requesting it to the vehicle unit for use by a predetermined application after decrypting it with a security unit in the second roadside unit. In this case, the application implies an application system for collecting a toll or the like such as a toll collection system in an expressway (e.g., so-called ETC system in Japan), a parking fee collection system in a time-charged parking space or the like. 
         [0031]    The wireless communication system described above is not necessarily in a communicable condition in terms of communication with the external memory medium when the vehicle unit communicates with the roadside unit. Therefore, for example, when the user uses a toll collection system that collects a toll at a toll booth of an exit from a toll road, the user is not obliged to re-insert the IC card into an IC card slot before passing through a toll booth after pulling the IC card out of the IC card slot at a service area or the like. Therefore, a user operation for inserting the IC card into the slot is saved in the situation described above. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which: 
           [0033]      FIG. 1  shows a block diagram of a wireless communication system in a first embodiment of the present disclosure; 
           [0034]      FIG. 2  shows a block diagram of a vehicle unit in the first embodiment of the present disclosure; 
           [0035]      FIGS. 3A and 3B  show block diagrams of a registration unit and a toll unit in the first embodiment of the present disclosure; 
           [0036]      FIG. 4  shows a sequence chart of a card information registration process to the vehicle unit in the first embodiment of the present disclosure; 
           [0037]      FIG. 5  shows a sequence chart of a toll collection process in the first embodiment of the present disclosure; 
           [0038]      FIG. 6  shows a sequence chart of a history storage process on an IC card in the first embodiment of the present disclosure; 
           [0039]      FIG. 7  shows a block diagram of a wireless communication system in a second embodiment of the present disclosure; 
           [0040]      FIGS. 8A and 8B  show block diagrams of the registration unit and the toll unit in the second embodiment of the present disclosure; 
           [0041]      FIG. 9  shows a sequence chart of a card information registration process to the vehicle unit in the second embodiment of the present disclosure; 
           [0042]      FIG. 10  shows a sequence chart of a toll collection process in the second embodiment of the present disclosure; 
           [0043]      FIG. 11  shows a block diagram of a wireless communication system in a third embodiment of the present disclosure; 
           [0044]      FIGS. 12A and 12B  show block diagrams of the vehicle unit and the cellular phone in the third embodiment of the present disclosure; 
           [0045]      FIG. 13  shows a block diagram of a card center server in the third embodiment of the present disclosure; 
           [0046]      FIG. 14  shows a sequence chart of a card ID registration process for the vehicle unit in the third embodiment of the present disclosure; 
           [0047]      FIG. 15  shows a flowchart of the card ID registration process in the vehicle unit in the third embodiment of the present disclosure; 
           [0048]      FIG. 16  shows a flowchart of the card ID registration process in the card center server in the third embodiment of the present disclosure; 
           [0049]      FIGS. 17A and 17B  show block diagrams of the vehicle unit and a roadside unit in a conventional system; and 
           [0050]      FIG. 18  shows a sequence chart of an encryption/decryption process in the conventional system. 
       
    
    
     DETAILED DESCRIPTION 
       [0051]    Embodiments of the present disclosure is described with reference to the accompanying drawings. In this case, the present disclosure of an invention is not limited to the embodiments in the following, but takes various forms as far as they belong to an art of the invention. 
       First Embodiment 
       [0052]    [Explanation of Configuration] 
         [0053]      FIG. 1  is a block diagram showing a constitution of a wireless communication system  10  in a first embodiment. The wireless communication system  10  equips the vehicle unit  20  carried by a vehicle, the registration unit  30  that is placed on a roadside in a service area, a parking area, a gas station and the like, a toll unit  40  that is placed on a roadside at an exit/entrance of a toll road, the parking area and the like and an information centre  70 . In addition,  FIG. 1  shows only one of the vehicle unit  20 , the registration unit  30  and toll unit  40  in the drawing, plural pieces of respective units are used in an actual system. Further, the registration unit  30  may be placed at an entrance of the toll road or the like with a distinguishing sign attached thereon to be clearly distinguishable from the toll unit  40  by the user. 
         [0054]    Next, the details of the vehicle unit  20  are explained by using a block diagram in  FIG. 2 . The vehicle unit  20  equips the radio antenna  21 , a DSRC unit  22 , an HMI  23 , a vehicle unit v-SAM  24 , an integrated circuit (IC) card interface (I/F)  25 , a memory  26  and a control unit  27 . 
         [0055]    The radio antenna  21  is used for Dedicated Short Range Communication (DSRC) that provides a wireless communication for narrow area communication. 
         [0056]    The DSRC unit  22  performs transmission and reception of information through the radio antenna  21  by DSRC. 
         [0057]    The HMI  23  is an interface unit offering Human Machine Interface for communication between a human being and a device. More practically, the interface consists of an operation button and/or LEDs. 
         [0058]    The vehicle unit v-SAM  24  performs encryption and decryption of information exchanged with the registration unit  30  and the toll unit  40  as well as encryption/decryption of vehicle unit information (i.e., a management number, a form registration number, the number of a vehicle and the like). 
         [0059]    The IC card interface  25  is an interface to communicate with IC cards  28   a ,  28   b ,  28   c , and retrieves information stored by the IC cards  28   a ,  28   b ,  28   c  as well as stores information in those IC cards  28   a ,  28   b ,  28   c . In this case, it is assumed that the IC card interface  25  is an interface of a contactless type in the present embodiment, but it may be configured as a contact type interface. In this case, the IC cards  28   a ,  28   b ,  28   c  use respectively different encryption method for storing information. 
         [0060]    The memory  26  consists of a device that does not require a memory content retaining operation for storing various information (e.g., a flash memory). 
         [0061]    The control unit  27  consists of a central processing unit (CPU), a ROM, a RAM, an I/O, and the like, and controls the DSRC unit  22 , the HMI  23 , the vehicle unit v-SAM  24 , the IC card interface  25  and the memory  26  are controlled in a unified manner. 
         [0062]    The details of the registration unit  30  registration are explained by using a block diagram in  FIG. 3A  in the following. The registration unit  30  equips the radio antenna  31 , the DSRC unit  32 , a road SAM  33 , a communication interface  34 , card SAMs  35 ,  36 ,  37  and a control unit  38 . 
         [0063]    The radio antenna  31  is an antenna for DSRC. The DSRC unit  32  uses the radio antenna  31  for performing transmission and reception of information by DSRC. 
         [0064]    The road SAM  33  is a unit having function of encrypting information (except for card information) to be transmitted to the vehicle unit  20  as well as function of decrypting encrypted information received from the vehicle unit  20  (except for card information). 
         [0065]    The communication interface  34  is an interface to communicate with the information center  70  through wired communication. 
         [0066]    The card SAMs  35 ,  36 ,  37  are used to encrypt and decrypt information by an encryption method applied to the information that is stored in the IC cards  28   a ,  28   b ,  28   c  that respectively correspond to the card SAMs  35 ,  36 ,  37 . 
         [0067]    The control unit  38  is a unit including a central processing unit (CPU), a ROM, a RAM, an I/O and the like, and controls the DSRC unit  32 , the road SAM  33 , the communication interface  34  and the card SAMs  35 ,  36 ,  37  in a unified manner. 
         [0068]    The details of the toll unit  40  are explained by using a block diagram in  FIG. 3B  in the following. The toll unit  40  equips a road SAM  43  and a communication interface  44  and card SAMs  45 ,  46 ,  47 , a control unit  48  as well as the radio antenna  41  and the DSRC unit  42 . 
         [0069]    The radio antenna  41  is an antenna for DSRC. The DSRC unit  42  uses the radio antenna  41  for performing transmission and reception of information by DSRC. 
         [0070]    The road SAM  43  is a unit having function of encrypting information (except for card information) to be transmitted to the vehicle unit  20  as well as function of decrypting encrypted information received from the vehicle unit  20  (except for card information). 
         [0071]    The communication interface  44  is an interface to communicate with information center  70  through wired communication. 
         [0072]    The card SAMs  45 ,  46 ,  47  are used to encrypt and decrypt information by an encryption method applied to the information that is stored in the IC cards  28   a ,  28   b ,  28   c  that respectively correspond to the card SAMs  35 ,  36 ,  37 . In this case, the toll unit  40  in the present embodiment has three card SAMs (that means the toll unit  40  accommodates at least three different applications), but may only have one card SAM. 
         [0073]    The control unit  48  is a unit including a central processing unit (CPU), a ROM, a RAM, an I/O and the like, and controls the DSRC unit  32 , the road SAM  33 , the communication interface  34  and the card SAMs  35 ,  36 ,  37  in a unified manner. 
         [0074]    The information center  70  is explained in the following. The information center  70  consists of a well-known server apparatus, and has function of storing registration information sent from the registration unit  30 , function of performing payment process based on payment information sent from the toll unit  40 . 
         [0075]    [Explanation of Operation] 
         [0076]    The operation of the wireless communication system  10  is explained in the following. 
         [0077]    (1) Card Information Registration Process 
         [0078]    First, a process of card information registration regarding information stored in the IC card (one of the IC card  28   a ,  28   b ,  28   c ) to be registered in the vehicle unit  20  is described with reference to a sequence chart in  FIG. 4 . In this case, a well-known portion of DSRC protocol is omitted from the description for conciseness and brevity. 
         [0079]    When the vehicle unit  20  receives a BST (Beacon Service Table) from the registration unit  30  after entering into a communication area of the registration unit  30  (S 105 ), the vehicle unit  20  sends a response request (“SELECT CARD” in the drawing) for the IC card (S 110 ). In this case, it is assumed that the IC card interface  25  of the vehicle unit  20  is impossible to communicate with the IC card (that is, it is assumed that the IC card is not in the proximity of the IC card interface  25 ). 
         [0080]    If there is no response from the IC card before a predetermined time, the vehicle unit  20  sends to the registration unit  30  a VST (Vehicle Service Table) for informing the registration unit  30  of an absence of the IC card (S 115 ). 
         [0081]    When the vehicle unit  20  receives the BST again from the registration unit  30  after a predetermined interval (S 120 ), the vehicle unit  20  sends the response request to the IC card (S 130 ). If the IC card is able to communicate with the IC card interface  25  (if there is the IC card in a proximity of the IC card interface  25 ), a response to the vehicle unit  20  from the IC card (ATR in the figure) is sent (S 135 ). Then, the vehicle unit  20  sends the VST to the registration unit  30  for informing the registration unit  30  of the presence of the IC card (S 140 ). 
         [0082]    Then, a mutual authentication is executed between the control unit  38  of the registration unit  30  and the vehicle unit  20  (S 150 ), and the mutual authentication is executed between the card SAM of the registration unit  30  (one of the card SAMs  35 ,  36 ,  37  corresponding to the encryption method used for the present IC card) and the IC card (S 155 ). 
         [0083]    The card information read instruction is transmitted to the vehicle unit  20  from the control unit  38  of the registration unit  30  if the mutual authentication is normal (S 160 ), and the vehicle unit  20  which received such instruction uses the IC card interface  25  to read the encrypted card information from the IC card (S 165 ). In this case, the “card information” means a card number, an expiration date, name information, a card issuer number, a card type, the money balance, use history information and the like. 
         [0084]    The vehicle unit  20  which has read the encrypted card information transmits the encrypted card information to the control unit  38  of the registration unit  30  (S 170 ). 
         [0085]    The control unit  38  of the registration unit  30  that received the encrypted card information passes the card information to one of the card SAMs corresponding to the card information (i.e., the card SAM that is capable of decrypting the card information) (S 175 ). The card SAM which received the encrypted card information decrypts the encrypted card information, and passes the decrypted information to the control unit  38  (S 180 ). 
         [0086]    The control unit  38  which received the decrypted card information verifies the card information (S 185 ). More practically, the control unit  38  verifies whether the decryption has been normal, whether the decrypted card information contains no discrepancy and the like. In this case, information may be retrieved from the information center  70  through the communication interface  34  for verification of the card information, or the card information may be transmitted to the information centre  70  for verification in the information centre  70 . 
         [0087]    If it is determined that the card information is normal, the registration unit  30  transmits the encrypted card information before decryption to vehicle unit  20  (S 190 ). In this case, the reason why transmits the encrypted card information to the vehicle unit  20  is to prevent substitution of the card information or the like during the verification process and to securely store the encrypted card information that is verified to be normal in the vehicle unit  20 . 
         [0088]    The vehicle unit  20  which received the encrypted card information stores the received information in the memory  26  (S 195 ). Thereafter, whenever transmission of the encrypted card information is requested by the toll unit  40 , the vehicle unit  20  transmits the card information that is stored in the memory  26  to the toll unit  40 , instead of retrieving the card information from the IC card, without determining that a communication with the IC card is possible. 
         [0089]    (2) Toll Collection Process 
         [0090]    A process for collecting a toll by a communication between the vehicle unit  20  and the toll unit  40  is described next with reference to a sequence chart in  FIG. 5 . In this case, a well-known portion of DSRC protocol is omitted from the description for conciseness and brevity. 
         [0091]    When the vehicle unit  20  receives the BST (Beacon Service Table) from the toll unit  40  after entering into a communication area (S 205 ), the vehicle unit  20  determines whether the IC card information of the application corresponding to the toll unit  40  in the memory  26 , and transmits the VST (Vehicle Service Table) to inform the toll unit  40  of the storage of the IC card information if the IC card information is stored in the toll unit  40  (S 210 ). 
         [0092]    Then, the mutual authentication is executed between the control unit  48  of toll unit  40  and the vehicle unit  20  (S 215 ). 
         [0093]    If the mutual authentication is normal, card information read instruction is transmitted to the vehicle unit  20  from the control unit  48  of toll unit  40  (S 225 ). Then, the control unit  27  of the vehicle unit  20  reads the encrypted card information memorized in the memory  26  and corresponding to a specified application (S 230 ). Then, the encrypted card information that has been read is transmitted to the toll unit  40  (S 235 ). 
         [0094]    The control unit  48  of the toll unit  40  that received the encrypted card information passes the card information to one of the card SAMs corresponding to the card information (the SAM that is capable of decrypting the card information) (S 240 ). The card SAM which received the encrypted card information passes the card information to the control unit  48  after decrypting the encrypted card information (S 245 ). 
         [0095]    The control unit  48  which received the decrypted card information performs a toll collection process (S 250 ). More practically, the control unit  48  performs a payment process by transmitting the card information through the communication interface  44 , or performs a process that reduces an amount of the money balance in the card information stored in the memory  26  of the vehicle unit  20 . 
         [0096]    (3) History Information Write Process 
         [0097]    A process for storing use history information to the memory  26  of the vehicle unit  20  by a communication between the vehicle unit  20  and the registration unit  30  is described with reference to a sequence chart in  FIG. 6 . In this case, a well-known portion of DSRC protocol is omitted from the description for conciseness and brevity. In addition, an initial process (equivalent to steps S 105  to S 155  in  FIG. 4 ) that is performed when the vehicle unit  20  enters into a communication area of the registration unit  30  is omitted from the description due to its similarity. 
         [0098]    When the initial process is finished, the vehicle unit  20  retrieves based on an input from the HMI  23  history Information of a specific service from the memory  26  (S 305 ). 
         [0099]    Then, the vehicle unit  20  transmits the history information which has been read from the memory  26  to the registration unit  30  (S 310 ). 
         [0100]    The control unit  38  of the registration unit  30  that received the history information passes the history information to the card SAM (one of the card SAMs  35 ,  36 ,  37  corresponding to the encryption method for use with the IC card in association with the above service) (S 315 ). 
         [0101]    The card SAM which received the history information passes the encrypted history information to the control unit  38  (S 320 ). 
         [0102]    The control unit  38  of the registration unit  30  that received the encrypted history information transmits the history information to the vehicle unit  20  (S 325 ). 
         [0103]    The vehicle unit  20  which received the encrypted history information writes the history information to the IC card through the IC card interface  25  (S 330 , S 335 ). When the vehicle unit  20  receives an end status that indicates that writing has finished from the IC card (S 340 ), the end status indicating that the writing has finished is transmitted from the vehicle unit  20  to the registration unit  30  (S 345 ). 
       Effect of the Present Embodiment 
       [0104]    Because a communicable condition to the IC card is not required at the time of the communication between the vehicle unit  20  and the toll unit  40 , the user of the communication system  10  is free from bothering, prior to passing through the toll gate, to insert the IC card into the vehicle unit  20  after pulling it out from the vehicle unit  20  at the service area or the like. 
         [0105]    Further, a decryption module for decrypting the encrypted card information is stored in the registration unit  30  and the toll unit  40 , thereby enabling the communication system  10  to accommodate a new encryption method in an easier manner. (This is because the number of the roadside units [the registration units and the toll units] is smaller than the number of the vehicle units in the communication system in operation) 
         [0106]    Furthermore, the information in the IC card is sent to the IC card after encryption (refer to  FIG. 6 ), thereby enabling a reduction of the number of the modules used in the communication system for achieving the same result. 
       Second Embodiment 
       [0107]    Though the registration unit  30  in the first embodiment transmits to the vehicle unit  20  the card information before decryption after verifying the card information by decrypting when the card information is received from the vehicle unit  20  (S 190 ), the card information which is used for verification after decryption may be transmitted to the vehicle unit after encryption by the road SAM  33 . In other words, the vehicle unit  20  may store the card information in a condition which can be decrypted by the road SAM  43  without using the card SAMs  45 ,  46 ,  47  in the toll unit  40 . The description in the second embodiment explains the above authentication scheme in detail. 
         [0108]    [Explanation of Configuration] 
         [0109]      FIG. 7  is a block diagram showing a constitution of a wireless communication system  15  in the second embodiment. The wireless communication system  15  equips the vehicle unit  20  carried by a vehicle, a registration unit  50  that is placed on a roadside in a service area, a parking area, a gas station and the like, a toll unit  60  that is placed on a roadside at an exit/entrance of a toll road, the parking area and the like, and an information centre  70 . Like parts have like numbers as used in the first embodiment, and description for the like parts is omitted. The information center  70  is described in the same manner. In addition,  FIG. 7  shows only one of the vehicle unit  20 , the registration unit  50  and the toll unit  60  in the drawing, plural pieces of respective units are used in an actual system. Further, the registration unit  50  may be placed at an entrance of the toll road or the like with a distinguishing sign attached thereon to be clearly distinguishable from the toll unit  60  by the user. 
         [0110]    The details of the registration unit  50  are explained by using a block diagram in  FIG. 8A . 
         [0111]    The registration unit  50  equips a road SAM  53 , a communication interface (I/F)  54 , card SAMs  55 ,  56 ,  57  and a control unit  58  as well as a radio antenna  51  and a DSRC unit  52 . 
         [0112]    The radio antenna  51  is an antenna for use in DSRC. The DSRC unit  52  uses the radio antenna  51  for performing transmission and reception of the information by DSRC. 
         [0113]    The road SAM  53  is a unit having function of encrypting information (including the card information) to be transmitted to the vehicle unit  20  as well as function of decrypting the encrypted information (except for the card information) which has been sent from the vehicle unit  20 . 
         [0114]    The communication interface  54  is an interface to communicate with the information center  70  through wired communication. 
         [0115]    The CARD SAMS 55 ,  56 ,  57  are used to encrypt and decrypt information by an encryption method applied to the information that is stored in the IC cards  28   a ,  28   b ,  28   c  that respectively correspond to the card SAMs  35 ,  36 ,  37 . 
         [0116]    The control unit  58  is a unit including a central processing unit (CPU), a ROM, a RAM, and an I/O and the like, and controls the DSRC unit  52 , the road SAM  53 , the communication interface  54  and the card SAMs  55 ,  56 ,  57  in a unified manner. 
         [0117]    The details of the toll unit  60  are explained by using a block diagram in  FIG. 8B  in the following. The toll unit  60  equips a road SAM  63 , a communication interface  64 , a control unit  65  as well as the radio antenna  61  and the DSRC unit  62 . 
         [0118]    The radio antenna  61  is an antenna for DSRC. The DSRC unit  62  uses the radio antenna  61  for performing transmission and reception of information by DSRC. 
         [0119]    The road SAM  63  is a unit having function of encrypting information (including card information) to be transmitted to the vehicle unit  20  as well as function of decrypting encrypted information received from the vehicle unit  20  (except for the card information). In addition, the encryption method used by the road SAM  63  is same as the encryption method used by the road SAM  53  of the registration unit  50 . In other words, the information encrypted by the road SAM  53  of the registration unit  50  can be decrypted by the road SAM  63 . 
         [0120]    The communication interface (I/F)  64  is an interface to communicate with information center  70  through wired communication. 
         [0121]    The control unit  65  consists of a central processing unit, ROM, an RAM, I/O, and it is the DSRC unit  62 , the road SAM  63  and a unit controlling the communication interface  64  for unification. 
         [0122]    The control unit  65  is a unit including a central processing unit (CPU), a ROM, a RAM, an I/O and the like, and controls the DSRC unit  62 , the road SAM  63 , the communication interface  64  in a unified manner. 
         [0123]    [Explanation of Operation] 
         [0124]    Operation of the wireless communication system  15  is explained in the following. 
         [0125]    (1) Card Information Registration Process 
         [0126]    First, a process of card information registration regarding information stored in the IC card (one of the IC card  28   a ,  28   b ,  28   c ) to be registered in the vehicle unit  20  is described with reference to a sequence chart in  FIG. 9 . In this case, a well-known portion of DSRC protocol is omitted from the description for conciseness and brevity. 
         [0127]    When the vehicle unit  20  receives a BST (Beacon Service Table) from the registration unit  50  after entering into a communication area of the registration unit  50  (S 405 ), the vehicle unit  20  sends a response request (“SELECT CARD” in the drawing) for the IC card (S 410 ). In this case, it is assumed that the IC card interface  25  of the vehicle unit  20  is impossible to communicate with the IC card (that is, it is assumed that the IC card is not in the proximity of the IC card interface  25 ). 
         [0128]    If there is no response from the IC card before a predetermined time, the vehicle unit  20  sends to the registration unit  50  a VST (Vehicle Service Table) for informing the registration unit  50  of an absence of the IC card (S 415 ). 
         [0129]    When the vehicle unit  20  receives the BST again from the registration unit  50  after a predetermined interval (S 420 ), the vehicle unit  20  sends the response request to the IC card (S 430 ). If the IC card is able to communicate with the IC card interface  25  (if there is the IC card in a proximity of the IC card interface  25 ), a response to the vehicle unit  20  from the IC card (ATR in the figure) is sent (S 435 ). Then, the vehicle unit  20  sends the VST to the registration unit  50  for informing the registration unit  50  of the presence of the IC card (S 440 ). 
         [0130]    Then, a mutual authentication is executed between the control unit  58  of the registration unit  50  and the vehicle unit  20  (S 450 ), and the mutual authentication is executed between the card SAM of the registration unit  50  (one of the card SAMs  55 ,  56 ,  57  corresponding to the encryption method used for the present IC card) and the IC card (S 455 ). 
         [0131]    The card information read instruction is transmitted to the vehicle unit  20  from the control unit  58  of the registration unit  50  if the mutual authentication is normal (S 460 ), and the vehicle unit  20  which received such instruction uses the IC card interface  25  to read the encrypted card information from the IC card (S 465 ). In this case, the “card information” means a card number, an expiration date, name information, a card issuer number, a card type, the money balance, use history information and the like. 
         [0132]    The vehicle unit  20  which has read the encrypted card information transmits the encrypted card information to the control unit  58  of the registration unit  50  (S 470 ). 
         [0133]    The control unit  58  of the registration unit  50  that received the encrypted card information passes the card information to one of the card SAMs corresponding to the card information (i.e., the card SAM that is capable of decrypting the card information) (S 475 ). The card SAM which received the encrypted card information decrypts the encrypted card information, and passes the decrypted information to the control unit  58  (S 480 ). 
         [0134]    The control unit  58  which received the decrypted card information verifies the card information (S 485 ). More practically, the control unit  58  verifies whether the decryption has been normal, whether the decrypted card information contains no discrepancy and the like. In this case, information may be retrieved from the information center  70  through the communication interface  54  for verification of the card information, or the card information may be transmitted to the information centre  70  for verification in the information centre  70 . 
         [0135]    If it is determined that the card information is normal, the control unit  58  of the registration unit  50  passes the decrypted card information to the road SAM  53  (S 487 ). The road SAM  53  which received the decrypted card information encrypts the card information and passes the information to the control unit  58  (S 488 ). 
         [0136]    The control unit  58  which received the encrypted card information transmits the card information to the vehicle unit  20  (S 490 ). 
         [0137]    The vehicle unit  20  which received the encrypted card information stores the received information to the memory  26  (S 495 ). Thereafter, whenever transmission of the encrypted card information is requested by the toll unit  60 , the vehicle unit  20  transmits the card information that is stored in the memory  26  to the toll unit  60 , instead of retrieving the card information from the IC card, without determining that a communication with the IC card is possible. 
         [0138]    (2) Toll Collection Process 
         [0139]    A process for collecting a toll by a communication between the vehicle unit  20  and the toll unit  60  is described next with reference to a sequence chart in  FIG. 10 . In this case, a well-known portion of DSRC protocol is omitted from the description for conciseness and brevity. 
         [0140]    When the vehicle unit  20  receives the BST (Beacon Service Table) from the toll unit  60  after entering into a communication area (S 505 ), the vehicle unit  20  determines whether the IC card information of the application corresponding to the toll unit  60  in the memory  26 , and transmits the VST (Vehicle Service Table) to inform the toll unit  60  of the storage of the IC card information if the IC card information is stored in the toll unit  60  (S 510 ). 
         [0141]    Then, the mutual authentication is executed between the control unit  65  of toll unit  60  and the vehicle unit  20  (S 515 ). 
         [0142]    If the mutual authentication is normal, card information read instruction is transmitted to the vehicle unit  20  from the control unit  65  of toll unit  60  (S 525 ). Then, the control unit  27  of the vehicle unit  20  reads the encrypted card information memorized in the memory  26  and corresponding to a specified application (S 530 ). Then, the encrypted card information that has been read is transmitted to the toll unit  60  (S 535 ). 
         [0143]    The control unit  65  of the toll unit  60  that received the encrypted card information passes the card information to the road SAM (S 540 ). The road SAM which received the encrypted card information passes the card information to the control unit  65  after decrypting the encrypted card information (S 545 ). 
         [0144]    The control unit  65  which received the decrypted card information performs a toll collection process (S 550 ). More practically, the control unit  65  performs a payment process by transmitting the card information through the communication interface  64 , or performs a process that reduces an amount of the money balance in the card information stored in the memory  26  of the vehicle unit  20 . 
         [0145]    (3) History Information Write Process 
         [0146]    A history information write process is same as the process of the history information in the first embodiment stated above. That is, the history information write process in the second embodiment substitutes the process regarding the toll unit  40  with the process regarding the toll unit  60 . Therefore, the description of the process is omitted. 
       Effect of the Present Embodiment 
       [0147]    The wireless communication system  15  has the same effect as the effect in the first embodiment. In addition, the wireless communication system  15  in the second embodiment has the following effects. 
         [0148]    The wireless communication system  15  in the second embodiment is not required to have the card SAM to accommodate each of encryption methods used in the IC card, because of the above-described operation scheme. 
       Third Embodiment 
       [0149]    [Explanation of Configuration] 
         [0150]      FIG. 11  is a block diagram showing a constitution of a wireless communication system  17  in the third embodiment. The wireless communication system  17  includes a vehicle unit  120  carried by a vehicle, a cellular phone  130  that can be carried by a user and the card center server  140  disposed in a credit card company. In this case, the vehicle unit  120  and the cellular phone  130  are communicable through DSRC, and a communication between the cellular phone  30  and the card center server  140  is provided through a wireless public communication network  150  of a cellular phone company or the like. In addition, though the cellular phone  130  and the wireless public communication network  150  are wirelessly connected, the card center server  140  and the wireless public communication network  150  are connected through wired communication. 
         [0151]    Next, the details of the vehicle unit  120  are explained by using a block diagram in  FIG. 12A . The vehicle unit  120  equips a radio antenna  121 , a DSRC unit  122 , a HMI  123 , a SAM  124 , a contactless communication interface (I/F)  125 , a memory  126  and a control unit  127 . 
         [0152]    The radio antenna  121  is used for Dedicated Short Range Communication (DSRC). 
         [0153]    The DSRC unit  122  uses the radio antenna  121  for performing transmission and reception of information by DSRC. 
         [0154]    The HMI  123  is a unit offering an interface (Human Machine Interface) for communication between a human being and a device. More practically, the interface consists of an operation button, LEDs and/or a speaker. 
         [0155]    The SAM  124  performs encryption and decryption of information communication with the roadside unit which is not illustrated, and encryption/decryption of the vehicle unit information (a management number, a form registration number, the number of a vehicle and the like). In addition, encryption/decryption of a credit card ID for the vehicle unit mentioned later is also performed by the SAM  124 . 
         [0156]    A contactless communication interface  125  is an interface to perform a short distance radio communication in a contactless manner with the cellular phone  130 . The contactless short distance radio communication may also be provided for a device such as a contactless type IC card through the interface  125  beside the communication with the cellular phone  130 . Further, in this case, the communication may be provided through a contact type communication interface. 
         [0157]    A memory  126  consists of a device that does not require a memory content retaining operation for storing various information (e.g., a flash memory). 
         [0158]    The control unit  127  consists of a central processing unit (CPU), a ROM, a RAM, an I/O, and the like, and controls the DSRC unit  122 , the HMI  123 , the SAM  124 , the contactless communication interface  125  and the memory  126  in a unified manner. 
         [0159]    The details of the cellular phone  130  are explained by using a block diagram in  FIG. 12B  in the following. The cellular phone  130  equips a radio antenna  131 , a public communication unit  132 , a HMI  133 , a SAM  134 , a contactless communication interface (I/F)  135 , a memory  136  and a control unit  137 . 
         [0160]    The radio antenna  131  is used for a wireless connection to the wireless public communication network  150 . 
         [0161]    The public communication unit  132  uses the radio antenna  131  for performing information transmission and reception through wireless communication (e.g., a CDMA communication or the like). 
         [0162]    The HMI  133  is a unit offering an interface (Human Machine Interface) for communication between a human being and a device. More practically, the interface consists of an operation button, a liquid crystal display, a speaker, a microphone and the like. 
         [0163]    The contactless communication interface  135  is an interface to perform the vehicle unit  120 . The communication through the interface  135  may also be provided for a device that uses the contactless short distance wireless communication beside the communication with the vehicle device  120 . Further, in this case, the communication may also be provided through a contact type communication interface. 
         [0164]    The memory unit  136  consists of a device that does not require a memory content retaining operation for storing various information (e.g., a flash memory). In this case, the memory  136  stores a credit ID for a cellular phone (i.e., an ID that is issued by a credit company for use in a payment). 
         [0165]    The control unit  137  consists of a central processing unit (CPU), a ROM, a RAM, an I/O, and controls the public communication unit  132 , the HMI  133 , the contactless communication interface  135  and the memory  136  in a unified manner. 
         [0166]    The details of the card center server  140  are explained by using a block diagram in  FIG. 13  in the following. 
         [0167]    The card center server  140  equips a public communication unit  142 , an HMI  143 , the SAM  144  and a vehicle card ID generator  145 . 
         [0168]    The public communication unit  142  uses the wireless public communication network  150  to perform communication with the cellular phone  130 . 
         [0169]    The HMI  143  is a unit offering an interface (Human Machine Interface) for communication between a human being and a device. More practically, the interface consists of a keyboard, a mouse, a display and the like. 
         [0170]    The SAM  144  is a unit having the same function as the SAM  124  of the vehicle unit  120 , and performs encryption/decrypting of communication information when the server  140  communicates with the vehicle unit  120  through the wireless public communication network  150  and the cellular phone  130 . Though the card center server  140  has the SAM  144  in the present embodiment, a different server may have the function that is equivalent to the SAM  144 , and the function on the different server may be employed for encryption/decryption. 
         [0171]    The vehicle card ID generator  145  generates a credit ID for a vehicle unit (a vehicle card ID hereinafter) based on a predetermined ID. The credit ID for a vehicle unit is the same kind of a credit ID for a cellular phone, and the credit ID for a vehicle unit is intended for storage in the vehicle unit. The credit ID for a vehicle unit is retrieved on demand for a payment process. 
         [0172]    [Explanation of Operation] 
         [0173]    Operation of the wireless communication system  17  is explained in the following. 
         [0174]    (1) Vehicle Card ID Registration Process (Whole Process). 
         [0175]    A whole process for registering a vehicle card ID to vehicle unit  120  is explained by using a sequence chart in  FIG. 14 . 
         [0176]    When a power supply for the vehicle unit  120  is turned on, the contactless communication interface  125  generates a card response request signal at a predetermined interval (S 605 ). The cellular phone  130  which received the response request responds to the response request with a response that indicates the presence of the card (S 610 ). Then, the vehicle unit  120  transmits a registration request to the cellular phone  130  (S 615 ). 
         [0177]    The cellular phone  130  which received the registration request transmits to the card center server  140  a registration request and the cellular phone card ID stored in the memory  126  (S 620 ). 
         [0178]    The control unit  147  of the card center server  140  which received the registration request and the cellular phone card ID performs verification of the cellular phone card ID (S 625 ). More practically, the control unit  147  verifies authenticity of the cellular phone card ID, determines whether an issuance of the vehicle card ID should be performed, and identifies a credit card holder corresponding to the cellular phone card ID. 
         [0179]    When the control unit  147  of the card center server  140  finishes verification of the cellular phone card ID, the control unit  147  transmits an instruction to the SAM  144  for performing a mutual authentication with the vehicle unit  120  (S 630 ). 
         [0180]    The SAM  144  which received the instruction of the mutual authentication performs the mutual authentication with the vehicle unit  120  (i.e., with the SAM  124  of the vehicle unit  120 ) after requesting the mutual authentication to the vehicle unit  120 . The mutual authentication may be performed by various methods such as a random number generation method. When the mutual authentication is successful, a communication channel for the encrypted information is established between the SAM  144  of the card center server  140  and the SAM  124  of the vehicle unit  120 , and the established channel is used for the subsequent communication between the vehicle unit  120  and the card center server  140 . In this case, the cellular phone  130  transmits the encrypted information that is received by the public communication unit  132  from the card center server  140  after making the encrypted information to be output as it is from the contactless communication interface  135  for transmission to the vehicle unit  120 , and transmits the encrypted information received by the contactless communication interface  135  from the vehicle unit  120  after passing the encrypted information to the public communication unit  132  as it is for transmission to the card center server  140  in the course of a transparent communication process. 
         [0181]    If the mutual authentication was successful, the SAM  144  of the card center server  140  transmits a notice that the mutual authentication is complete to the control unit  147  (S 640 ). 
         [0182]    The control unit  147  of the card center server  140  which received the completion notice of the mutual authentication generates the vehicle card ID for a the credit card holder identified in step S 625  (S 645 ). 
         [0183]    The control unit  147  of the card center server  140  instructs the SAM  144  to transmit the generated vehicle card ID to the vehicle unit  120  after encryption (S 650 ). 
         [0184]    The SAM  144  of the card center server  140  which received a transmission instruction encrypts the vehicle card ID, and transmits the encrypted vehicle card ID to the vehicle unit  120  through the cellular phone  130  after outputting the encrypted vehicle card ID from the public communication unit  142  to the public communication network  150  (S 655 ). 
         [0185]    The vehicle unit  120  which received the vehicle card ID decrypts the received card ID by using the SAM  124  for storage in the memory  126  (S 660 ). Then, the vehicle unit  120  transmits a completion notice that indicates the completion of storage to the card center server  140  when storage of the card ID is completed (S 665 ). 
         [0186]    The SAM  144  of the card center server  140  which received the completion notice decrypts the completion notice and passes the notice to the control unit  147  (S 670 ). The control unit  147  which received the completion notice relays the completion notice to the cellular phone  130  (S 675 ). 
         [0187]    The cellular phone  130  which received the completion notice notifies the user of the cellular phone  130  about the completion from the HMI  133  (S 680 ). For example, a message “Vehicle card ID registration completed” is displayed on a display unit. 
         [0188]    In a subsequent process, when the vehicle unit  120  receives a vehicle card ID retrieval request from a roadside unit or the like, the vehicle card ID is encrypted by the SAM  124  to be transmitted to the roadside unit through the DSRC unit  122  according to the above-described registration process for storing the vehicle card ID in the vehicle unit  120 . In this case, because the transmission process is identical with the toll collection process in the first and second embodiments, description of the transmission process is omitted. 
         [0189]    (2) Vehicle Card ID Registration Process (Vehicle Unit Side) 
         [0190]    The details of a process performed by the control unit  127  of the vehicle unit  120  in the Vehicle card ID registration process (Whole process) stated above are described with reference to a flowchart in  FIG. 15 . In this case, the vehicle card ID registration process (Vehicle unit side) is initiated when an electric power is supplied to the vehicle unit  120 . 
         [0191]    The control unit  127  of the vehicle unit  120  transmits a card response request when the vehicle card ID registration process (Vehicle unit side) is started through the contactless communication interface  125  (S 705 ). Then, whether the contactless communication interface  125  has any response in a predetermined period (e.g., within 10 seconds) is determined (S 710 ). When a response is detected (S 710 :YES), the process proceeds to step S 715 . When a response is not detected (S 710 :NO), the process remains in the present step until the response is detected. 
         [0192]    The control unit  127  determines whether the device which has responded to the request can be utilized for the vehicle card ID registration in step S 715  that comes after a determination that the response is detected. When the device is determined to be utilized (S 715 :YES), the process proceeds to step S 720 . When the device is determined not to be utilized (S 715 :NO), the process proceeds to step S 755 . 
         [0193]    The control unit  127  transmits the registration request to the device that has responded (i.e., to the cellular phone  130 ). 
         [0194]    Then, a mutual authentication with the card center server  140  is performed upon having a request from the card center server  140  (S 725 ). More practically, the SAM  124  of the vehicle unit  120  and the SAM  144  of the card center server  140  perform the mutual authentication with each other. 
         [0195]    Then, it is determined whether the mutual authentication is successful (S 730 ). When the mutual authentication is successful (S 730 :YES), the process proceeds to step S 735 . When the mutual authentication is not successful (S 730 :NO), the process proceeds to step S 750 . In this case, when the mutual authentication is successful, a channel for the encrypted information to be exchanged between the SAM  144  of the card center server  140  and the SAM  124  of the vehicle unit  120  is established, and the channel is used for communication between the vehicle unit  120  and the card center server  140  thereafter. 
         [0196]    The control unit  127  receives the vehicle card ID in step S 735  that comes after a determination that the mutual authentication is successful. That is, the control unit  127  receives the vehicle card ID transmitted from the card center server through the cellular phone  130 . 
         [0197]    The control unit  127  stores (i.e., registers) the vehicle card ID in the memory  126  upon receiving it. Then, the control unit  127  notifies the card center server  140  of the completion of the registration via the cellular phone  130  (S 745 ). Then, the present process (Vehicle card ID registration process (Vehicle unit side)) is concluded. 
         [0198]    On the other hand, the control unit  127  notifies the card center server  140  of an error via cellular phone  130  in step S 750  that comes after a determination that the mutual authentication is not successful. Then, the process proceeds to step S 755 . 
         [0199]    In step S 755 , the error is notified to a user of the vehicle unit  120 . More practically, for example, an LED is lit for indicating that the registration of vehicle card ID to the vehicle unit has failed with an accompanying guidance message output from a speaker. Then, the present process (Vehicle card ID registration process (Vehicle unit side)) is concluded. 
         [0200]    (3) Vehicle Card ID Registration Process (Card Center Server Side) 
         [0201]    The details of a process performed by the control unit  147  of the card center server  140  in the Vehicle card ID registration process (Whole process) stated above are described with reference to a flowchart in  FIG. 16 . In this case, the vehicle card ID registration process (Card center server side) is initiated when an electric power is supplied to the card center server  140 . 
         [0202]    When the vehicle card ID registration process (Card center server side) in the control unit  140  of the card center server control unit  147  is started, the control unit  147  determines whether any request of registration from the vehicle unit  120  is received (S 805 ). When the registration request is determined to be received (S 805 :YES), the process proceeds to step S 810 . When the request is determined not to be received (S 805 :NO), the process remains at the present step until it receives the request. 
         [0203]    In step S 810  that comes after a determination that the registration request is received, the cellular phone card ID is verified. More practically, the control unit  147  verifies authenticity of the cellular phone card ID, determines whether an issuance of the vehicle card ID should be performed, and identifies a credit card holder corresponding to the cellular phone card ID. 
         [0204]    Then, it is determined whether a verification result of the cellular phone card ID is correct (S 815 ). When the card ID is determined to be correct (S 815 :YES), the process proceeds to step S 820 . When the card ID is determined not to be correct (S 815 :NO), the process proceeds to step S 860 . 
         [0205]    In step S 820  that comes after a determination that the cellular phone card ID is correct, a mutual authentication instruction is issued to the SAM  144  for performing the authentication with the vehicle unit  120 . The SAM  144  which received an instruction to perform the mutual authentication performs the mutual authentication after requesting the mutual authentication to the vehicle unit  120  (i.e., the SAM  124  of the vehicle unit  120 ). Then, the SAM  144  notifies the control unit  147  of the completion of the mutual authentication when the mutual authentication is successful. 
         [0206]    In step S 830 , the process branches according to the result of the mutual authentication. That is, whether the mutual authentication is successful or not affects the process. When the mutual authentication is successful (S 830 :YES), the process proceeds to step S 835 . When the process is not successful (S 830 :NO), the process proceeds to step S 860 . 
         [0207]    In step S 835  that comes after a determination that the mutual authentication is successful, the vehicle card ID generator  145  is instructed to generate a vehicle card ID. Then, the generated vehicle card ID is encrypted by the SAM  144  to be transmitted to the vehicle unit  120  through the cellular phone  130  (S 840 ). 
         [0208]    Then, a notice from the vehicle unit  120  is received (S 845 ). The notice is either of a normal end notice which indicates that the vehicle unit  120  has received the vehicle card ID and its registration has been complete (i.e., the notice in step S 745  described above), or an error notice which indicates that the vehicle unit  120  has received the vehicle card ID and its registration has not been successful (i.e., the notice in step S 750  described above). 
         [0209]    Then, in step S 850 , the process determines whether the notice received in step S 845  is the normal end notice. When the notice is determined to be the normal end notice (S 850 :YES), the process proceeds to step S 855 . When the notice is determined to be the error notice (S 850 :NO), the process proceeds to step S 860 . 
         [0210]    In step S 855  which comes after a determination that the notice is the normal end notice, the process notifies the cellular phone  130  of the normal end of the process. The notice of the normal end is intended for displaying the normal end of the process on a display of the cellular phone  130 . Then, the present process (Vehicle card ID registration process (Card center server side)) concludes itself. 
         [0211]    In step S 860 , the process notifies the cellular phone  130  of the error in the process. The notice of the error is intended for displaying the error in the process on the display of the cellular phone  130 . Then, the present process (Vehicle card ID registration process (Card center server side)) concludes itself. 
       Effect of the Present Embodiment 
       [0212]    The wireless communication system  17  in the third embodiment can store the vehicle card ID to the memory  126  without any specific device (e.g., the registration unit or the like), and can send the ID to the vehicle unit  120  only when the issuance of the ID is approved on the card center server side. Therefore, the usability by the user of the credit card is improved without compromising the reliability of the credit card system. 
         [0213]    Further, the card ID is encrypted in the card center server  140  and decrypted in the vehicle unit  120 , thereby making it difficult to eavesdrop the card ID in the course of communication. 
         [0214]    Furthermore, the vehicle unit  120  and the server  140  perform the mutual authentication prior to the communication, thereby effectively preventing the fraud such as a spoofing or the like. 
         [0215]    Furthermore, the registration of the ID in the vehicle unit  120  is sent to the server  140  through the cellular phone  130 , which is then redirected to be returned the cellular phone  130 . In this manner, the registration of the ID in the vehicle unit  120  as well as the registration notice to the card center server  140  are transmitted and notified to the user of the cellular phone  130 . Therefore, the user of the credit card can have an improved sense of security. 
       Other Embodiments 
       [0216]    Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. 
         [0217]    (1) In the first embodiment described above, there are two types of the roadside unit, that is, the registration unit  30  and the toll unit  40  in the wireless communication system. However, the roadside unit having the function of both types in one body may be used to produce the same effect. The system in the second embodiment may have the same modification. 
         [0218]    (2) In the first embodiment described above, the information is first encrypted by the SAM in the registration unit  30  to be stored in the IC card. However, the information retrieved from the memory  26  of the vehicle unit  20  may be stored in the IC card without encryption depending on the type of the information. 
         [0219]    In this manner, the registration unit  30  may be omitted from an information writing process to write the information in the IC card, thereby allowing the information to be stored in the IC card when the communication to the registration unit  30  is not available. The same advantage may apply to the second embodiment. 
         [0220]    (3) The wireless communication system  17  in the third embodiment stores the ID in the memory  136  of the cellular phone  130 , and sends the ID to the server  140 . However, the ID sent from the memory  136  may be substituted with an input of ID/password, other specific codes or the like from operation buttons on the cellular phone  130 , and the server  140  may verify the inputted ID/password on the server side. In this manner, the same advantage is achieved as the third embodiment. 
         [0221]    Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.