Abstract:
An electronic key executes keyless entry communication or RFID communication. A wireless controller mounted on a vehicle executes keyless entry communication within a range of a radius of several meters to several tens of meters. An RFID reader is assigned to each door and executes RFID communication within a range of a radius of approximately 1 meter. In regards to unlocking the door, the wireless controller issues a password by the keyless entry communication, and a wireless circuit temporarily stores the issued password. The RFID readers search for the password stored in the electronic key by the RFID communication, and the wireless controller unlocks a door corresponding to the RFID reader for which the password was detected.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority to Japanese Patent Application 2014-047098 filed on Mar. 11, 2014 and is a Continuation Application of PCT/JP2015/056136 filed on Mar. 3, 2015, the entire contents of each application are hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a door unlocking system and a door unlocking method and, more particularly, relates to a door unlocking system and a door unlocking method to exclusively unlock some of a plurality of doors of a vehicle. 
         [0004]    2. Description of the Related Art 
         [0005]    A keyless entry system is known that unlocks doors of a vehicle by utilizing a wireless signal between a key carried by a user and a wireless device mounted on the vehicle. In this system, normally, when the user pushes an unlock button of the portable key, all the doors of the vehicle are unlocked. However, simultaneously unlocking all the doors leads to a security problem because, for example, when the user gets in the driver&#39;s seat, a suspicious person may enter the interior of the vehicle from the passenger&#39;s side of the vehicle. 
         [0006]    In this regard, JP 2009-79418 A discloses a system changing the number of doors to be unlocked, based on positional information of a vehicle. This system enables provision of control such as unlocking only the door on the side of the driver&#39;s seat when it is determined that a vehicle is located in a relatively unsafe area, based on GPS information. 
         [0007]    However, the system of JP 2009-79418 A uses GPS information and therefore has a complicated circuit configuration. Additionally, it is difficult to provide a boundary of safety around an area in which a vehicle is located and a risk of a suspicious person getting into a vehicle is not necessarily eliminated even in a safe area, resulting in a limited user&#39;s convenience. 
       SUMMARY OF THE INVENTION 
       [0008]    Preferred embodiments of the present invention provide a door unlocking system and a door unlocking method enabling simplification of a circuit configuration and enhancement of a user&#39;s convenience. 
         [0009]    A door unlocking system according to a preferred embodiment of the present invention includes a portable device carried by a user and performing a wireless communication following a first short-range wireless communication mode and a wireless communication following a second short-range wireless communication mode; a first in-vehicle device mounted on a vehicle including a plurality of doors, the first in-vehicle device performing the wireless communication following the first short-range wireless communication mode in a first range; and a plurality of second in-vehicle devices mounted on the vehicle respectively correspondingly to the plurality of doors and each performing the wireless communication following the second short-range wireless communication mode in a second range smaller than the first range, the first in-vehicle device including a password generator issuing a password to the portable device in the first short-range wireless communication mode, the portable device including a storage temporarily storing a password issued by the password generator, the plurality of second in-vehicle devices each including a password detector searching for a password stored in the storage in the second short-range wireless communication mode, the first in-vehicle device further including an unlocking actuator unlocking a door corresponding to the second in-vehicle device including the password detector detecting the password stored in the storage. 
         [0010]    Preferably, the password issued by the password generator has contents updated each time the number of times of issuance reaches a reference value. 
         [0011]    Preferably, the portable device further includes an indicator notifying the first in-vehicle device of an unlocking operation by the user, and the password generator issues the password in response to a notification from the indicator. 
         [0012]    Preferably, the portable device includes a passive wireless communication tag in accordance with the second short-range wireless communication mode. 
         [0013]    Preferably, the plurality of second in-vehicle devices covers respective ranges independent of each other as the second range. 
         [0014]    A door unlocking method according to another preferred embodiment of the present invention is a door unlocking method performed by a door unlocking system including a portable device carried by a user and performing a wireless communication following a first short-range wireless communication mode and a wireless communication following a second short-range wireless communication mode, a first in-vehicle device mounted on a vehicle including a plurality of doors, the first in-vehicle device performing the wireless communication following the first short-range wireless communication mode in a first range, and a plurality of second in-vehicle devices mounted on the vehicle respectively correspondingly to the plurality of doors and each performing the wireless communication following the second short-range wireless communication mode in a second range smaller than the first range, the method including an issuing step in which the first in-vehicle device issues a password to the portable device in the first short-range wireless communication mode; a storing step in which the portable device temporarily stores a password issued in the issuing step; a searching step in which each of the plurality of second in-vehicle devices searches for a password stored in the storing step in the second short-range wireless communication mode; and an unlocking step in which the first in-vehicle device unlocks a door corresponding to the second in-vehicle device detecting the password stored in the storing step. 
         [0015]    The first in-vehicle device issues a password in the first short-range wireless communication mode when a user carrying the portable device approaches the vehicle or when the user manually performs the unlocking operation of the portable device. The issued password is stored in the portable device. The second in-vehicle device corresponding to the door approached by the user detects the password stored in the portable device in the second short-range wireless communication mode. The first in-vehicle device exclusively unlocks the door corresponding to the second in-vehicle device detecting the password, i.e., the door approached by the user. Since a series of the processes described above is implemented in the short-range wireless communication modes, the circuit configuration is simplified. Since the door approached by the user is exclusively unlocked, the risk of a suspicious person getting into the vehicle from another door is prevented and the user&#39;s convenience is enhanced. 
         [0016]    The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a block diagram of an example of a configuration of a door unlocking system according to the example. 
           [0018]      FIG. 2  is a schematic of an example of a positional relation between a communication range of a keyless entry communication mode and an electronic key. 
           [0019]      FIG. 3  is a schematic of an example of a positional relation between a communication range of an RFID communication mode and the electronic key. 
           [0020]      FIG. 4  is a schematic of an example of a communication operation between the electronic key and a vehicle control apparatus. 
           [0021]      FIG. 5  is a flowchart of an example of an operation of a control circuit disposed in the electronic key. 
           [0022]      FIG. 6  is a flowchart of an example of an operation of an RFID-IC disposed in the electronic key. 
           [0023]      FIG. 7  is a flowchart of a portion of an operation of an ECU/BCM disposed in the vehicle control apparatus. 
           [0024]      FIG. 8  is a flowchart of another portion of the operation of the ECU/BCM disposed in the vehicle control apparatus. 
           [0025]      FIG. 9  is a flowchart of a portion of an operation of an RFID-IC disposed in the vehicle control apparatus. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Referring to  FIGS. 1 to 3 , a door unlocking system according to a preferred embodiment of the present invention includes an electronic key (portable device)  10  carried by a user, and a vehicle control apparatus  30  mounted on a vehicle (automobile) VL including doors DR 1  to DR 3 . The door DR 1  is disposed on a right side portion of the vehicle VL, the door DR 2  is disposed on a left side portion of the vehicle VL, and the door DR 3  is disposed on a rear portion of the vehicle VL. 
         [0027]    The electronic key  10  includes an unlock button  12  operated by a user, a wireless circuit  14  performing a wireless communication in a keyless entry (a wireless entry system for a vehicle using a remote key (an electronic key); also referred to as smart entry, keyless access, or a number of other names) communication mode (first short-range wireless communication mode), and an RFID tag  16  performing a wireless communication in an RFID communication mode (second short-range wireless communication mode). The wireless circuit  14  includes a control circuit  18  and an antenna  20 . The RFID tag  16  is a passive RFID tag and includes an RFID-IC  22  and an antenna  24 . The unlock button  12  is connected to the control circuit  18 . The control circuit  18  is connected through the I 2 C (Inter-Integrated Circuit) interface  26  to the RFID-IC  22 . 
         [0028]    The vehicle control apparatus  30  includes a wireless controller (first in-vehicle device)  32  performing a wireless communication in the keyless entry communication mode, RFID readers (second in-vehicle devices)  34   a  to  34   c  each performing a wireless communication in the RFID communication mode, and lock mechanisms  36   a  to  36   c  locking/unlocking the doors DR 1  to DR 3 , respectively. The RFID reader  34   a  is disposed in the vicinity of the door DR 1 , the RFID reader  34   b  is disposed in the vicinity of the door DR 2 , and the RFID reader  34   c  is disposed in the vicinity of the door DR 3 . 
         [0029]    The wireless controller  32  includes an ECU/BCM (Electronic Controller/Body Control Module)  38  and an antenna  40 . The RFID reader  34   a  includes an RFID-IC  42   a  and an antenna  44   a , the RFID reader  34   b  includes an RFID-IC  42   b  and antenna  44   b , and the RFID reader  34   c  includes an RFID-IC  42   c  and an antenna  44   c . The ECU/BCM  38  is connected through the I2C interface  46  to the RFID-ICs  42   a  to  42   c.    
         [0030]    In the keyless entry communication mode, a range of several meters to several dozen meters in radius is set as a communication range, and communications are performed by using high-frequency signals preferably in the LF band (125 KHz band) and the UHF band (315 MHz band in Japan and US, 433 MHz band in Europe), for example. On the other hand, in the RFID communication mode, a range of approximately 1 m in radius is preferably set as a communication range, and communications are performed by using high-frequency signals preferably in the UHF band (900 MHz band), for example. 
         [0031]    Because of differences in frequency and directivity of antennas, the communication range of the keyless entry communication mode radially spreads from the center of the vehicle VL, while the communication range of the RFID communication mode spreads from each of the doors DR 1  to DR 3  as a base point to the outside of the vehicle VL since the RFID tag is a passive RFID tag. The communication range of the RFID communication mode is smaller than the communication range of the keyless entry communication mode (see  FIGS. 2 and 3 ). The three communication ranges respectively covered by the RFID readers  34   a  to  34   c  are independent or substantially independent of each other (not overlapped or substantially not overlapped with each other or different from each other in the directionality of the antennas of the RFID readers), and the communication range covered by the wireless controller  32  covers all the three communication ranges respectively covered by the RFID readers  34   a  to  34   c.    
         [0032]    The electronic key  10  includes a small-sized primary battery (not shown) built-in, and the vehicle VL is equipped with a large-sized secondary battery (not shown). In the electronic key  10 , the power of the primary battery is supplied only to the wireless circuit  14 . In contrast, in the vehicle control apparatus  30 , the power of the secondary battery is supplied to all of the wireless controller  32 , the RFID readers  34   a  to  34   c , and the lock mechanisms  36   a  to  36   c.    
         [0033]    A user is able to exclusively unlock the door approached by the user out of the doors DR 1  to DR 3  disposed on the vehicle VL, by using the electronic key  10 . In this case, the keyless entry communication or the RFID communication is executed between the electronic key  10  and the vehicle control apparatus  30  in the order shown in  FIG. 4 . 
         [0034]    First, when the unlock button  12  disposed on the electronic key  10  is operated, the control circuit  18  notifies the ECU/BCM  38  of an unlocking request. This notification includes a description of a unique key code. This notification is transmitted in the keyless entry communication mode to the ECU/BCM  38 . 
         [0035]    If the key code included in the received unlocking request notification is successfully authenticated, the ECU/BCM  38  generates a password (random number or cryptography key) and returns the generated password to the control circuit  18  of the electronic key  10  that is the source of notification of the unlocking request. The password is a one-time password (One Time Password) having contents updated each time and is returned in the keyless entry communication mode to the control circuit  18 . Once the return is completed, the ECU/BCM  38  activates the RFID-ICs  42   a  to  42   c  disposed on the RFID readers  34   a  to  34   c  and starts searching for the RFID tag  16 . 
         [0036]    When receiving the password from the ECU/BCM  38 , the control circuit  18  of the electronic key  10  temporarily stores this password in a memory (not shown) in the RFID-IC  22 . The RFID readers  34   a  to  34   c  activated by the ECU/BCM  38  start searching for the RFID tag  16  of the electronic key  10 . When any of the RFID readers detects the RFID tag  16 , i.e., when the RFID tag  16  comes into the communication range of any of the RFID readers, the unique ID of the RFID tag  16  is utilized to start an authentication work thereof. If this authentication is successful, the RFID-IC with the successful RFID authentication issues a password request to the RFID tag  16 . This password request is repeatedly transmitted in the RFID communication mode. 
         [0037]    When the password request is received, the RFID-IC  22  disposed in the RFID tag  16  returns the password stored in the memory in the RFID communication mode to the request source (any one of the RFID-ICs  42   a  to  42   c ). When receiving the password from the electronic key  10 , the request source RFID-IC internally transfers this password via the I2C interface  46  to the ECU/BCM  38 . 
         [0038]    The ECU/BCM  38  checks the transferred password against the password issued in the manner described above. If the result of the checking indicates “matching,” the ECU/BCM  38  exclusively unlocks the lock mechanism corresponding to the RFID-IC that has transferred the password, out of the lock mechanisms  36   a  to  36   c . For example, if the transfer source of the password is the RFID-IC  42   c , the lock mechanism  36   c , i.e., the door DR 3 , is unlocked. The RFID readers  34   a  to  34   c  are stopped after the unlocking is completed. 
         [0039]    The control circuit  18  disposed in the electronic key  10  executes a process according to a flowchart shown in  FIG. 5  in association with unlocking of the doors DR 1  to DR 3 . This process is repeatedly executed every several milliseconds, for example. 
         [0040]    First, it is determined at step S 1  whether the unlock button  12  is operated. If the determination result is NO, the process is terminated, or if the determination result is YES, the process goes to step S 3 . At step S 3 , the wireless controller  32  disposed on the vehicle VL is notified of an unlocking request. This notification includes a description of a unique key code. This notification is transmitted in the keyless entry communication mode to the wireless controller  32 . 
         [0041]    When the notification is completed, it is determined at step S 5  whether a password is received from the wireless controller  32  in the keyless entry communication mode, and it is determined at step S 7  whether a time-out has occurred (a predetermined time has elapsed after the notification of the unlocking request). If the determination result of step S 5  is YES, the process goes to step S 9  and the received password is stored in the memory (not shown) in the RFID-IC  22 . When the storage is completed, the process is terminated. If the determination result of step S 7  is YES, the process is terminated without going through step S 9 . 
         [0042]    The RFID-IC  22  disposed in the electronic key  10  executes a process according to a flowchart shown in  FIG. 6  in association with unlocking of the doors DR 1  to DR 3 . This process is repeatedly executed every several milliseconds in an activated state based on an externally received wireless signal. 
         [0043]    First, it is determined at step S 11  whether a password request is received. If the determination result is YES, the process goes to step S 13 , and the password stored in the memory by the process of step S 9  described above is returned in the RFID communication mode to the request source. When the return is completed, the process is terminated. If the determination result of step S 11  is NO, the process is terminated without going through step S 13 . 
         [0044]    The ECU/BCM  38  disposed in the vehicle control apparatus  30  executes a process according to flowcharts shown in  FIGS. 7 and 8  in association with unlocking of the doors DR 1  to DR 3 . This process is also repeatedly executed every several milliseconds, for example. 
         [0045]    It is determined at step S 21  whether a notification of an unlocking request is made in the keyless entry communication mode, and it is determined at step S 23  whether a key code described in the notification is successfully authenticated. If either the determination result of step S 21  or the determination result of step S 23  is NO, the process is terminated. In contrast, if both the determination result of step S 21  and the determination result of step S 23  are YES, the process goes to step S 25 . 
         [0046]    A password is generated at step S 25 , and the generated password is issued to the notification source of the unlocking request at step S 27 . The password is transmitted in the keyless entry communication mode to the notification source. When the transmission is completed, the process goes to step S 29  and the RFID readers  34   a  to  34   c  are activated. 
         [0047]    It is determined at step S 31  whether the password is transmitted via the I2C interface  46  from any one of the RFID-ICs  42   a  to  42   c , and it is determined at step S 33  whether a time-out has occurred (a predetermined time has elapsed after the process of step S 29 ). If the determination result of step S 31  is YES, the process goes to step S 35 , and it is determined whether the transferred password matches the password issued at step S 25 . 
         [0048]    If the determination result of step S 35  is YES, the process goes to step S 37  to unlock the lock mechanism corresponding to the transfer source of the password out of the lock mechanisms  36   a  to  36   c . After the unlocking is completed, the RFID readers  34   a  to  34   c  are stopped at step S 39 , and the process is subsequently terminated. If the determination result at step S 33  is YES or the determination result of step S 35  is NO, the RFID readers  34   a  to  34   c  are stopped at step S 39  without executing the process of step S 37 , and the process is subsequently terminated. 
         [0049]    Each of the RFID-ICs  42   a  to  42   c  disposed in the vehicle control apparatus  30  executes a process according to a flowchart shown in  FIG. 9  in association with unlocking of the doors DR 1  to DR 3 . This process is also repeatedly executed every several milliseconds, for example. 
         [0050]    At step S 41 , searching for the RFID tag  16  is started. When the RFID tag  16  is found, the process goes to step S 43  to execute an authentication, i.e., an RFID authentication, utilizing the unique ID of the RFID tag  16 . It is determined at step S 45  whether the RFID authentication is successful and, if the determination result is NO, the process is terminated, or if the determination result is YES, the process goes to step S 47 . 
         [0051]    At step S 47 , a password request is issued in the RFID communication mode. It is determined at step S 49  whether the password is received from the RFID tag  16  in the RFID communication mode, and it is determined at step S 51  whether a time-out has occurred (a predetermined time has elapsed after the issuance of the password request). 
         [0052]    If the determination result of step S 49  is YES, the process goes to step S 53 , and the received password is internally transferred via the I2C interface  46  to the ECU/BCM  38 . When the transfer is completed, the process is terminated. In contrast, if the determination result of step S 51  is YES, the process is terminated without going through step S 53 . 
         [0053]    As can be seen from the above description, the electronic key  10  is carried by a user and executes respective wireless communications following the keyless entry communication mode and the RFID communication mode. The wireless controller  32  is mounted on the vehicle VL and performs a wireless communication following the keyless entry communication mode in a range of several meters to several dozen meters in radius. The RFID readers  34   a  to  34   c  are mounted on the vehicle VL respectively correspondingly to the doors DR 1  to DR 3  and each perform a wireless communication following the RFID communication mode in a range of approximately 1 m in radius, for example. In association with unlocking of the doors DR 1  to DR 3 , the wireless controller  32  disposed on the vehicle VL issues a password to the electronic key  10  in the keyless entry communication mode (S 25  to S 27 ), and the wireless circuit  14  disposed in the electronic key  10  temporarily stores the issued password (S 5 , S 9 ). Each of the RFID readers  34   a  to  34   c  disposed on the vehicle VL searches for the password stored in the electronic key  10  in the RFID communication mode (S 41  to S 51 ). The wireless controller  38  exclusively unlocks the door corresponding to the RFID reader detecting the password, out of the doors DR 1  to DR 3  (S 37 ). 
         [0054]    Since a series of the processes described above is implemented by utilizing the keyless entry communication mode and the RFID communication mode, the circuit configuration is simplified. Since the door approached by the user is exclusively unlocked, the risk of a suspicious person getting into the vehicle VL from another door is prevented and the user&#39;s convenience is enhanced. Since a one-time password updated at each issuance is utilized, the security is maintained. 
         [0055]    In this example, the password is issued in response to an operation of the unlock button  12  disposed on the electronic key  10 . However, the wireless controller  32  disposed on the vehicle control apparatus  30  may repeatedly issue a response request to the electronic key  10  and, when the electronic key  10  returns a response signal thereto, i.e., when the electronic key  10  comes into the communication area of the wireless controller  32 , the password may be issued from the vehicle control apparatus  30  to the electronic key  10 . 
         [0056]    In this example, the contents of the password are updated each time the password is issued once. However, the contents of the password may be updated each time the password is issued the predetermined number of times equal to or greater than two. 
         [0057]    In this example, the door approached by the user is exclusively unlocked without exception. However, whether to exclusively unlock the door approached by the user or simultaneously unlock the doors DR 1  to DR 3  maybe switched depending on a user setting. In particular, for example, the electronic key may have two buttons, i.e., a button for unlocking only the door approached by the user and a button for the simultaneous unlocking, or the switching is able to be performed such that a system for unlocking only the door approached by the user is activated when the unlock button is pushed once, while a system for simultaneously unlocking all the doors is activated when the unlock button is pushed twice. 
         [0058]    Although this example is described in terms of a three-door type vehicle having three doors in the left and right side portions and the rear portion (hatch) of the vehicle, the vehicle may be a five-door type vehicle. In the case of the five-door type, an RFID reader may be disposed for each of five doors, or a common RFID reader may be disposed for two doors (for front and rear seats) on the right side and a common RFID reader may be disposed for two doors (for front and rear seats) on the left side. 
         [0059]    Correlation between the claims and features of preferred embodiments of the present invention will hereinafter be described. S 25  to S 27  of the flowchart correspond to a password generator or an issuing step recited in the claims. S 5  and S 9  of the flowchart correspond to a storage or a storing step recited in the claims. S 41  to S 51  of the flowchart correspond to a password detector or a searching step recited in the claims. S 37  of the flowchart corresponds to an unlocking actuator or an unlocking step recited in the claims. S 1  to S 3  of the flowchart correspond to an indicator recited in the claims. 
         [0060]    While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.