JP2008007974A - Authentication device, portable machine, and base station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an authentication device which prevents response signals from respective keys as radio communication portable machines from interfering with each other, and correctly receives the response signals, when the plurality of keys exist in an area where a signal from a vehicle body or the like as a base station can be received. <P>SOLUTION: The portable machines B1 to B3 transmit response pulses RP having respective predetermined pulse widths to an ID signal IA transmitted from the base station, and after the transmission of the response pulses RP, the portable machines B1 to B3 wait for a signal from the base station over a predetermined waiting time TW. On the other hand, the base station transmits a challenge response CR upon termination of the response pulses RP transmitted from the portable machines. The pulse widths of the response pulses RP of the respective portable machines B1 to B3 are different from each other, and therefore the base station transmits the challenge response CR upon termination of the pulse having the longest pulse width. Herein the waiting time TW is set shorter than a difference of the pulse widths, and therefore the portable machines other than the portable machine B3 having the longest pulse width cannot obtain the signal during the waiting time TW, to thereby terminate operation of the portable machines other than the portable machine B3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an authentication apparatus including a signal collision prevention system in a keyless entry system, and more specifically, a plurality of keys that are wireless communication portable devices in an area where a signal from a vehicle body or the like as a base station can be received. The present invention relates to an authentication apparatus, a portable device, and a base station, each having a system that prevents mutual interference of key response signals when present.

  In recent years, it is called a keyless entry system, etc., and performs desired operations such as locking and unlocking or engine start using radio wave or infrared communication without relying on mechanical key contact operations such as inserting a key into a keyhole. There is an authentication device. An authentication device that realizes a keyless entry system includes a portable device (key) possessed by an automobile owner and a base station incorporated on the automobile side. 2. Description of the Related Art Conventionally, authentication apparatuses that transmit ID data and the like from a portable device by pressing a button on the portable device, and perform authentication of ID data and a desired operation to a base station have been widely known.

  On the other hand, in recent years, ID data or the like is transmitted first from the base station side by an operation such as pulling a knob on the door of an automobile as a base station, and the portable device transmits a signal in response to the transmission data of the base station. The authentication device can be seen. Furthermore, there is also an authentication device that performs communication by transmitting ID data and the like between the base station and the portable device only by allowing the user to bring the portable device closer to the base station by causing the base station to transmit signals at regular time intervals. It can be seen.

  As described above, in a system in which the user does not operate the portable device, for example, when the user pulls the door knob in a state where the user has a plurality of portable devices (spare keys), the plurality of portable devices are connected to the base station. Since the response signals are generated in response to the signals simultaneously, the response signals interfere with each other and the base station cannot receive the signals normally.

  Hereinafter, a means for preventing signal collision in the conventional authentication apparatus will be described.

  The portable device stores unique ID data in the memory, and the base station adds the ID data of any one of the portable devices to the beginning or end of the transmission signal and transmits it. The portable device is set to issue a response signal only when the ID data stored in its own memory matches the ID data added to the transmission signal of the base station. Therefore, even if there are a plurality of portable devices in an area where the transmission signal of the base station can be received and a response signal can be returned to the base station (hereinafter referred to as a communication area), only one portable device can communicate with the other party. Can be selected and communicated.

However, there may be no portable device that matches the ID data added to the transmission signal of the base station in the communication area. In such a case, as shown in FIG. 10, the base station transmits ID data of another portable device after a certain period of time has elapsed. For example, when the portable devices 1 to 10 are provided, the portable device existing in the communication area can be changed by sequentially changing the portable device ID added to the communication data from the portable device 1 to the portable device 10 ID. You can find them to scan in order. As described above, in the conventional keyless entry system, the base station selects a specific portable device as a communication partner by adding the ID data of the portable device to the transmission signal and transmits it, thereby preventing mutual interference of response signals. It was.
US Pat. No. 5,793,324 US Pat. No. 6,963,270 Special table 2001-511276 gazette

  In the conventional example, when N mobile devices are provided as spare keys, the base station needs to store ID data of a total of N + 1 mobile devices in the memory. Furthermore, when there is only one portable device in the communication area, the base station needs to perform data transmission a maximum of N + 1 times. Therefore, when the number of spare keys is large, the memory area for storing the ID data of the portable device is increased on the base station side, and time waste and power consumption in communication are increased. In addition, since the base station transmits the ID data of all the portable devices to the outside in order, the number of portable devices is detected, leading to a decrease in security.

  According to the present invention, in a keyless entry system, even when a plurality of spare keys are provided, communication can be performed in a short time and power consumption can be reduced. In addition, the base station does not need to store the ID data of the portable device in the memory, so that the memory area can be saved and the scale of the circuit and program can be reduced. Furthermore, since the base station does not transmit the ID data of the portable device to the outside, it is possible to prevent a decrease in security due to leakage of ID data.

  In the present invention, the base station receives response pulses of various pulse widths from a plurality of portable devices within the communication area. Since the pulse widths are different from each other, the response pulse stops in order from the portable device in which the short pulse width is set. The base station transmits communication data such as a challenge response after confirming that the response pulse intensity has decreased in order and that all the portable devices have no response pulse. In this way, in the present invention, since the communication data is transmitted after receiving the response pulse for a relatively long time and confirming the end of the response pulse, it is possible to reduce the occurrence of errors. When the pulse width of the response pulse is extremely short, an error such as reception of noise or the like as a response pulse is likely to occur.

  Furthermore, if the base station stores the shortest pulse width among the response pulses of a plurality of mobile devices, when the response pulse is received and the end of the pulse is detected in a shorter time, the signal will be noise. It can be determined that

  In addition, although it has been described that the response pulse is transmitted for a long time, the response pulse is relatively short when compared with communication data such as ID data, so that power consumption and communication time are not significantly affected.

  In particular, in the first embodiment of the present invention, when the end of the response pulse is confirmed, the base station immediately transmits communication data, so that time spent in communication is small. On the other hand, in the second embodiment, the operation of one portable device is continued by the operation continuation command, and the operations of the other portable devices are stopped. Therefore, it is possible to prevent the portable device from malfunctioning due to reception of noise or the like.

  FIG. 1 is a block diagram of an authentication apparatus according to the present invention. The portable device B represents one of a plurality of portable devices. Both the base station A and the portable device B have transmitters 4 and 9 and front ends 5 and 10 and can transmit and receive data. The front ends 5 and 10 include a signal input stage, an intermediate amplification stage, and a demodulated signal output.

  The data transmitted from the transmitter and the timing of transmission are controlled by the microcomputers 3 and 8. Counters 2 and 7 are connected to the microcomputers 3 and 8 and can operate at predetermined time intervals. Furthermore, the microcomputer 8 of the portable device B can encrypt the random number (challenge response) transmitted from the base station A using a predetermined encryption program. On the contrary, the microcomputer 3 of the base station B can receive the encrypted random number (challenge response) from the portable device B and then decrypt it with a predetermined decryption program to obtain the original random number (challenge response). .

  The base station A and the portable device B have flash memories 1 and 6 inside. In the flash memory of the base station A, ID data unique to the base station A and a command pattern for designating the operation of the portable device are stored. On the other hand, the flash memory 6 of the portable device B stores ID data of the base station A, ID data unique to the portable device B, and a command pattern.

  Hereinafter, based on an Example, operation | movement of the authentication apparatus based on this invention is demonstrated concretely.

  A first embodiment of the present invention will be described. First, FIG. 2 shows transmission data of the base station A and the portable device B. Here, it is assumed that there are three portable devices B1 to B3 for one base station, and each transmission data is illustrated along the time axis. More specifically, the transmitters 4 and 9 of the base station A and the portable device B transmit a carrier having a constant frequency in the range drawn in a pulse shape, and communication is performed on the carrier by ASK modulation or FSK modulation. Information is transmitted by adding data. The frequency of the carrier wave is about 350 MHz. When FSK modulation is employed, frequency modulation is preferably performed within a range of about ± 30 kHz. When ASK modulation is employed, modulation is preferably performed with an amplitude width of about 2 μVpp.

  Furthermore, when there are a plurality of portable devices B, there is a possibility that other portable devices B and the transmission signal of the base station A may interfere with each other. Therefore, it is desirable to cause the base station A and the portable device B to transmit different frequency carriers. The modulation method and the carrier frequency may be the same not only in the first embodiment but also in other embodiments.

  Next, operations of the base station A and the portable device B will be described along the flowchart shown in FIG. First, when the user performs an operation such as pulling the door knob 11 of the base station A, a communication start signal is applied from the door knob 11 to the microcomputer 3. When communication starts, the microcomputer 3 first accesses the flash memory 1, reads the wake pattern WP and base station ID data IA, and then transmits the wake pattern WP and ID data IA by the transmitter 4 (step A101). , A102). The wake pattern WP is a signal having a predetermined pattern, and the portable device B is set to start communication only when the wake pattern WP is received. The ID data IA is ID data unique to the base station A stored in the memory 1.

  The ID data of the base station A is also stored in the flash memory 6 on the portable device B side. The ID data IA transmitted from the base station A is received by the front end 10 and is flashed by the microcomputer 8 in the portable device B. The ID data of the base station A stored in the memory 6 is collated. When the coincidence is not confirmed, the portable device B ends the communication (step B116). In this way, by performing the collation in Step B103, for example, the portable device B reacts to a signal emitted from a base station such as a car body of an adjacent different vehicle type, or a portable device of a different vehicle type carried by the user. It is possible to prevent malfunction such as reaction.

  When collation of the ID data IA is obtained, a response pulse RP having a predetermined pulse width is transmitted by the transmitter 8 of the portable device B (steps B103 to B106). Here, the pulse width of the response pulse RP is set to a different length for each portable device B. The range of the pulse width of the response pulse RP is determined according to the clock speed of the microcomputer 3 on the base station B side. If the clock speed is high, even shorter pulses can be properly received. In general, it is appropriate to set the pulse width of several tens of microseconds to several milliseconds as the shortest pulse width and to each portable device B with a pulse width that is a constant multiple of that.

  On the other hand, on the base station A side, the elapsed time Tb1 after the ID data IA transmission is measured by the counter 2 until the portable device B transmits the response pulse RP (steps A103 to A105). In the base station A, the standby time TS is set, and when the response pulse RP is not obtained before the elapsed time Ta1 reaches the standby time TS, the base station A ends the communication. When the response pulse RP is obtained within the response time TS, the base station A waits until the response pulse RP is stopped, and when the stop of the response pulse RP is confirmed, the base station A transmits a challenge response CR (step). A106 to A108).

  In the first embodiment, since the response pulse RP is transmitted as soon as the reception and authentication of the ID data IA are completed, the waiting time TS is shortened and the response time is shortened especially when the operation of the microcomputer 9 is fast. If the pulse RP is not obtained, the communication can be stopped immediately.

  On the portable device B side, after the response pulse RP is transmitted, the elapsed time Tb1 is measured again by the counter, and the challenge response CR is kept waiting until the reception time TW elapses (steps B106 to B108). If the challenge response CR cannot be received even after the reception time TW has elapsed, the communication ends (step B112).

  The communication in step B112 is terminated by stopping the power supply of the portable device B, stopping the operation of the entire portable device B, the microcomputer 8 and the front end 10, or by performing program control of the microcomputer 8. A method is conceivable in which B is insensitive to a signal transmitted from the base station A and a response signal is not transmitted. Further, after a certain period of time, the insensitive state may be recovered. The method for terminating the communication and stopping the demodulation function may be the same in the second embodiment.

  Here, steps B107 and B108 will be described with reference to FIG. As described above, the portable device B transmits response pulses RP each having a different pulse width. When there are a plurality of portable devices B in the communication area, the plurality of portable devices B transmit response pulses RP all at once (step B104) from the time when the base station A finishes transmitting the ID data IA (step A103). Begin. Although the base station A receives a plurality of response pulses RP, since the pulse widths of the response pulses RP are all different, the intensity of the response pulse RP decreases stepwise with time, and finally, within the communication area. All the portable devices B stop transmitting the response pulse RP.

  The portable device that has finished transmitting the response pulse RP sequentially enters a signal waiting state from the base station (step B106). Since the signal waiting state is set to continue only during the reception time TW, the portable device B ends its operation in order as time elapses (steps B108 to B112).

  On the other hand, when the base station A recognizes that all the response pulses RP have stopped, it transmits a challenge response CR. However, in reality, the base station A may continue to receive a weak noise signal. Therefore, the point in time at which the received signal becomes equal to or less than a certain intensity may be regarded as the end of response pulse reception. That is, a threshold is set according to the modulation degree of ASK modulation or FSK modulation, and it can be considered that all response pulses RP are stopped when the level of the received signal becomes equal to or lower than the threshold. For example, when ASK modulation is performed with an amplitude width of about 2 μVpp, it can be recognized that all the response pulses RP from the base station B are stopped when the level of the received signal becomes 1 μVpp or less. The setting of the threshold may be the same in the second embodiment described below.

  Taking FIG. 2 as an example, the challenge response CR is transmitted after the response pulse RP of the portable device B3 stops. At this time, the portable device B3 has entered the reception time TW, but the other portable devices have already finished the reception time TW and have all finished their operations. Therefore, only the portable device B3 can receive the challenge response CR and perform communication for authentication.

  As shown in FIG. 3, the pulse width of the response pulse is set to increase by ΔTR for each portable device B. Furthermore, the reception time TW is set to be shorter than ΔTR to prevent a plurality of portable devices B from entering the reception state at the same time.

  The transmitted challenge response CR is received and demodulated by the portable device B, and then the data structure such as the bit length is confirmed by the microcomputer 8 (step B109). When it is determined that the data structure is correct, the challenge response CR is encrypted by the microcomputer 8 with a predetermined program and transmitted from the transmitter 9 as communication data TD (steps B110 and B111).

  The communication data TD is received and demodulated by the front end 10 of the base station A, and then decoded by the microcomputer 3 with a predetermined program (steps A109 and A110). The microcomputer 3 determines whether or not the decryption result of the communication data TD matches the challenge response CR (step A111).

  If the portable device B used by the user is compatible with the base station A, the decryption program of the base station A is encrypted by the portable device B regardless of the value of the challenge response CR. It is possible to appropriately decrypt the data and obtain a challenge response CR that is the original value. When security enhancement is required, it is desirable that the challenge response CR is generated by the random number generation program in the microcomputer 3 of the base station A, and further the bit length is increased.

  If the match of the challenge response CR is confirmed, a desired operation such as unlocking the door is performed (A112). After performing the above steps, the base station A and the portable device B end communication (steps A113 and B112).

  As described above, in the first embodiment, the portable device transmits a response pulse having a unique length to each portable device. Since a response pulse with a constant intensity is received for a relatively long time and communication data such as a challenge response is transmitted after confirming the end of the pulse, there are few errors. In particular, if the base station stores the shortest pulse width among the response pulses of a plurality of mobile devices, when the end of the pulse is detected in a shorter time when receiving the response pulse, the signal will be noise. It can be determined that

  In practice, communication data such as ID data is often much longer than the response pulse. Therefore, even if a response pulse RP having a long pulse width is transmitted in the first embodiment, the influence on power consumption and communication time is not large.

  Next, a second embodiment will be described with reference to FIGS. Similar to the first embodiment, also in the second embodiment, the response pulse RP transmitted from the portable device B has a predetermined pulse width. The pulse width is unique to each portable device B, and pulses having the same width are not transmitted. (Steps A201 to A204 and B201 to B204).

  However, unlike the first embodiment, in the second embodiment, when the response pulse RP is received from the portable device B in step A205, the operation continuation command CC is transmitted (step A205).

  The operation continuation command CC will be described below.

  In the flash memory 6 of the portable device B, an operation continuation command CC is stored. The operation continuation command CC is unique to each portable device. Here, the operation continuation command of the portable device Bn is expressed as CCn.

  On the other hand, the base station A stores the operation continuation command CC of the portable device B and the pulse width of the response pulse RP in the flash memory 1 in association with each other.

  As described above, the portable device B transmits response pulses RP each having a different pulse width. When there are a plurality of portable devices B in the communication area, the plurality of portable devices B start transmitting the response pulse RP at the same time (step B204) from the time when the base station A finishes transmitting the ID data IA (step A202). ). Although the base station A receives a plurality of response pulses RP, the pulse widths of the response pulses RP are all different. Therefore, as shown in FIG. 4, the intensity of the response pulse RP decreases stepwise as time passes. Go. Eventually, all the portable devices B in the communication area stop the response pulse RP. At this time, the base station A measures the time TRP from the end of transmission of the ID data IA or the start of reception of the response pulse RP to the end of reception of the response pulse RP.

  Actually, since the base station A may continue to receive weak noise signals, the point in time when the received signal becomes equal to or less than a certain intensity may be regarded as the end of response pulse reception.

  The time TRP measured by the base station A in the above process should match the longest pulse width among the pulse widths set for the plurality of portable devices B in the communication area. Therefore, the base station A refers to the list of pulse widths of the response signal RP stored in the flash memory 1 and identifies the portable device Bm that matches the measurement time TRP.

  Next, the base station A transmits an operation continuation command CCm corresponding to the portable device Bm in step A204. Since the microcomputer 8 of the portable device Bn is set to stop the operation when the operation continuation command CCn stored in the flash memory 6 is not received within a certain time after the response pulse RP is transmitted, All the portable devices B other than the device Bm stop operating. In the example of FIG. 8, m = 3, and only the portable device B3 continues to operate.

  Subsequently, the base station A transmits a challenge response CR (step A206), and the subsequent operations are the same as those in the first embodiment. When the coincidence of ID data is confirmed, the portable device A performs a predetermined operation. To end communication (steps A207 to A211, B206 to B210).

  As described above, in the second embodiment, the portable device B transmits a response pulse having a specific length, as in the first embodiment. Therefore, like the first embodiment, the second embodiment has an effect that an error due to reception of noise or the like can be prevented.

  Furthermore, in the second embodiment, since only the portable device B that has received the operation continuation command CC is designed to continue the operation, the base station A reliably selects one portable device B as the communication partner. It becomes possible to prevent errors.

  In the first and second embodiments, it has been described that it is possible to prevent malfunction when the user carries a key of a different vehicle type by transmitting / receiving the wakeup pattern WP and the ID data IA. . However, for example, when the user carries a key (portable device B ′) of the same vehicle type but with a different vehicle body, the key responds to the wake-up pattern WP and the ID data IA and transmits a response pulse RP. . As a result of transmitting the response pulse RP, a challenge response CR is transmitted from the base station A, but authentication fails due to incompatibility of the data structure or mismatch of the decoding results. Furthermore, in the first and second embodiments, even if the user carries another key (portable device B) that can be unlocked, the delay time of the portable device B ′ can be shorter than that. In this case, the portable device B cannot be used for authentication, and the authentication failure is repeated by the portable device B ′.

  That is, in the embodiment according to the present invention, even if the user carries another key (portable device B) that can be unlocked, if the delay time of the portable device B ′ is longer than that, the portable device B Cannot be used for authentication. Therefore, it is desirable to store the longest pulse width TPR obtained in the communication. As a result, when the authentication fails by the portable device B ′, the next communication performed within a certain period of time communicates the portable device B ′ by transmitting a challenge response CR or an end command before the pulse width TPR. It is possible to select the other portable device B carried by the user as a communication partner.

  Finally, the application of the present invention will be described. The above embodiment has been described by taking an in-vehicle keyless entry system as an example. However, the authentication device, base station, and portable device according to the present invention can be applied to other systems. For example, in a store, a restaurant, a library, etc., an IC tag (mobile device) capable of communication is provided for each product, tableware, book, etc., and the IC tag is read using a reader (base station). It can be applied to electronic tag management for reading product information and the like. In particular, as described above, the delay time TR and the pulse width TPR of the response pulse RP obtained in the communication are stored in the flash memory of the base station, and the mobile phone that has already been authenticated each time communication is performed. By setting to exclude machines in order, information can be sequentially read from a plurality of portable devices placed at predetermined positions, particularly using a stationary base station. As a result, it is possible to reliably read information on products placed in the cart, tableware placed on the tray, and stacked books.

It is a block diagram which shows the structure of the authentication apparatus by this invention. In the 1st Example of this invention, it is a wave form diagram of the signal transmitted / received by a base station and a portable device. It is a flowchart which shows operation | movement of the base station and portable device in 1st Example of this invention. In the 2nd Example of this invention, it is a wave form diagram of the signal transmitted / received by a base station and a portable device. It is a flowchart which shows operation | movement of the base station and portable machine in 2nd Example of this invention. In a prior art example, it is a wave form diagram of the signal transmitted / received by a base station and a portable device.

Explanation of symbols

1 Flash Memory 2 Counter 3 Microcomputer 4 Transmitter 5 Front End 6 Flash Memory 7 Counter 8 Microcomputer 9 Transmitter 10 Front End 11 Door Knob

Claims (8)

A portable device that performs authentication by transmitting and receiving signals to and from a base station,
The portable device receives a signal from the base station;
A second step of transmitting a response signal having a predetermined pulse width;
A portable device that performs authentication with a base station in a third step of waiting for a signal from the base station for a predetermined waiting time.   The said 3rd step WHEREIN: When the signal from a base station is not obtained during the said waiting | standby time, it becomes insensitive to the signal transmitted from the said base station after that. The portable device described. A portable device that performs authentication by transmitting and receiving signals to and from a base station,
The portable device receives a signal from the base station;
A second step of transmitting a response signal having a predetermined pulse width;
Thereafter, authentication with the base station is performed in a third step of receiving a command signal instructing whether or not the signal transmitted from the base station is insensitive.   An authentication apparatus comprising the base station according to claim 1 and the portable device. A base station that performs authentication by transmitting and receiving signals to and from a portable device,
The base station stores in advance the pulse width of the signal transmitted by the portable device,
A base station that measures a time from a predetermined time point to a time point when a signal received from the portable device has an intensity equal to or lower than a predetermined threshold value. A base station that performs authentication by transmitting and receiving signals to and from a portable device,
The base station stores in advance the pulse width of the signal transmitted by the portable device,
A base station that transmits a predetermined signal when a signal received from the portable device has an intensity equal to or lower than a predetermined threshold.   The base station according to claim 6, wherein the predetermined signal is a command signal instructing whether or not the portable device will respond to a transmission signal from the base station thereafter. 8. An authentication apparatus comprising the base station according to claim 5 and the portable device.