JP2011208463A - On-vehicle wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily determine whether a relay lies between a portable machine and an on-vehicle wireless communication device in an on-vehicle wireless communication system for intercommunicating between the portable machine and the on-vehicle wireless communication device mounted on a vehicle.SOLUTION: The portable machine 200 replies an analog signal for detection that has the same waveform at a transmitting/stopping interval Taccording to the request from the on-vehicle wireless communication device 100. The on-vehicle wireless communication device 100 rotates the phase of the received signal for detection 180 degrees in the condition of keeping the waveform thereof, and synthesizes a signal for detection delayed in only the same time as the transmitting interval Tand a signal for detection replied after the transmitting interval Tfrom the delayed signal for detection and not delayed at an all path filter 311. Then, it is determined using the synthesized signal whether intercommunication with the portable machine 200 is performed directly.

Description

  The present invention relates to an in-vehicle wireless communication system that performs mutual communication between a portable device and an in-vehicle wireless communication device mounted on a vehicle.

  Conventionally, as an example of an in-vehicle wireless communication system that performs mutual communication between a portable device and an in-vehicle wireless communication device mounted on a vehicle, there is a technique described in Patent Document 1.

  The passive entry disclosed in Patent Document 1 prevents theft of a vehicle using a repeater (so-called relay attack), and the vehicle door is operated even though the portable device is located away from the vehicle. If it is done, an anti-theft function is provided to invalidate the operation.

  This passive entry consists of an in-vehicle transceiver and one or more portable transceivers. The on-vehicle transceiver generates a request signal (hereinafter also referred to as a request signal). When the portable transceiver receives the request signal, it transmits an answer signal (hereinafter also referred to as a response signal) in response to the request signal. And a vehicle-mounted transceiver will lock / unlock a vehicle door, if a response signal is received.

  Moreover, the vehicle-mounted transceiver has time measuring means for measuring the time from when the request signal is transmitted until when the response signal is received. When the response signal is received, it is recognized as a normal response signal only when the time value of the time measuring means is within a preset effective time value, and the vehicle door is locked / unlocked.

  When a repeater is interposed between the in-vehicle transceiver and the portable transceiver, from the transmission of the request signal from the in-vehicle transceiver to the reception of the request signal in the portable transceiver, the response to the reception of the request signal Since the time value of the elapsed time until the response signal is transmitted from the portable transmitter / receiver and the response signal is received by the in-vehicle transmitter / receiver is delayed by the repeater, it does not fall within the preset effective time value.

  Therefore, when the time value of the time measuring means exceeds the preset effective time value, the vehicle-mounted transceiver performs locking / unlocking of the vehicle door even when the response signal is received. Therefore, the vehicle can be prevented from being stolen by the relay attack.

Japanese Patent Laid-Open No. 2003-13644

  However, in the above passive entry, whether the elapsed time from the transmission of the request signal from the in-vehicle transceiver to the reception of the response signal in the in-vehicle transceiver has exceeded a predetermined effective time value, If it is attempted to increase detection accuracy in order to determine whether or not a repeater is present, it may be determined that a repeater is present even if the response signal is from a legitimate portable device. Therefore, for example, it is necessary to accurately detect the rising edge and the falling edge of the request signal and the response signal and accurately measure the elapsed time.

  The present invention has been made in view of the above problems, and in an in-vehicle wireless communication system that performs mutual communication between a portable device and an in-vehicle wireless communication device mounted on a vehicle, the present invention is provided between the portable device and the in-vehicle wireless communication device. An object is to easily determine whether or not a repeater is interposed.

In order to achieve the above object, the invention described in claim 1
In response to a request signal transmitted within a predetermined range from an in-vehicle wireless communication device provided in the vehicle, the portable device performs mutual communication in which a response signal including an identification code is returned within the predetermined range, thereby The wireless communication device receives a response signal from the portable device, collates the identification code included in the response signal with a registered code registered in advance, and controls locking and unlocking of the vehicle door according to the collation result In-vehicle wireless communication system
The in-vehicle wireless communication device transmits a request signal as a request signal to return a detection signal having a predetermined waveform at a predetermined transmission interval,
In response to the signal, the portable device returns a detection signal having a predetermined waveform at a predetermined transmission interval.
In-vehicle wireless communication device
A delay means for rotating the phase by 180 degrees while retaining the waveform of the received detection signal and delaying the detection signal by the same time as the transmission interval;
A synthesizing unit that synthesizes the detection signal delayed by the delay unit and the detection signal that is returned to the detection signal at a transmission interval and is not delayed by the delay unit;
And determining means for determining whether or not the in-vehicle wireless communication device and the portable device are directly communicating with each other using the combined signal synthesized by the synthesizing means.

  In such an in-vehicle wireless communication system that performs mutual communication between the portable device and the in-vehicle wireless communication device mounted on the vehicle, a fraud is performed by interposing a repeater between the portable device and the in-vehicle wireless communication device. May be. Thus, when a repeater is interposed between the portable device and the in-vehicle wireless communication device, for example, the waveform of the detection signal changes due to the influence of a band-pass filter or the like provided in the repeater.

  Therefore, the present invention returns a detection signal having a predetermined waveform from the portable device at a predetermined transmission interval. When no repeater is interposed between the in-vehicle wireless communication device and the portable device, the detection signal transmitted at a predetermined transmission interval is transmitted to the in-vehicle wireless communication device with the transmission interval at the time of transmission. . In contrast, when a repeater is interposed between the in-vehicle wireless communication device and the portable device, transmission is performed at a predetermined transmission interval due to a change in the waveform of the detection signal as described above. The detected signal may be transmitted to the in-vehicle wireless communication device with the interval changing from the transmission interval at the time of transmission.

  Therefore, the transmission interval of the detection signal and the time delayed by the delay means are the same, the phase of the detection signal delayed by the delay means is rotated by 180 degrees, and the synthesized signal synthesized by the synthesizing means is There is a significant difference between the case where the wireless communication device and the portable device directly communicate with each other (without the repeater) and the case where the wireless communication device does not directly communicate with each other (with the repeater).

  As described above, in the present invention, since the entire waveforms of the two detection signals are used (synthesized), it is determined whether the in-vehicle wireless communication device and the portable device are directly communicating with each other. It is relatively easy to determine whether or not a repeater is interposed between a portable device and an in-vehicle wireless communication device, as compared with a case where a rising edge or a falling edge of a signal is detected with high accuracy. it can.

  According to another aspect of the present invention, the determining means smoothes the synthesized signal synthesized by the synthesizing means, integrates the smoothed smoothed signal, compares the accumulated value with a predetermined value, If the measured value exceeds the predetermined value, it is determined that the in-vehicle wireless communication device and the portable device are not directly communicating with each other. If the predetermined value is not exceeded, the in-vehicle wireless communication device and the portable device communicate with each other. You may make it determine with performing directly.

  As described above, by using the integrated value, it is easy to determine whether or not the in-vehicle wireless communication device and the portable device are directly communicating with each other even when the detection signal is attenuated. it can.

  Further, as the determination means, as shown in claim 3, the determination means calculates the phase change amount in the synthesized signal synthesized by the synthesis means, compares the phase change amount with a predetermined value, If the amount of change exceeds a predetermined value, it is determined that the in-vehicle wireless communication device and the portable device are not directly communicating with each other. If the predetermined amount is not exceeded, the in-vehicle wireless communication device and the portable device communicate with each other. You may make it determine with performing directly.

  Further, as shown in claim 4, an all-pass filter can be employed as the delay means.

  Moreover, as shown in claim 5, the in-vehicle wireless communication device may include a changing unit that changes a transmission interval and a time for delaying the detection signal.

  This is preferable because confidentiality can be improved.

It is a block diagram which shows schematic structure of the vehicle-mounted radio | wireless communications system in embodiment of this invention. It is a block diagram which shows schematic structure of the receiver in embodiment of this invention. It is a block diagram which shows schematic structure of the determination circuit part in embodiment of this invention. It is a wave form diagram which shows the signal for a detection in embodiment of this invention. (A) is a waveform diagram of a signal that has passed through the all-pass filter, and (b) is a waveform diagram of a signal that has not passed through the all-pass filter. (A) is a waveform diagram of signals A and B when no repeater is interposed, and (b) is a waveform diagram of signals A and B when a repeater is interposed. (A) is a waveform diagram after synthesis when no repeater is interposed, and (b) is a waveform diagram after synthesis when a repeater is interposed. (A) is the integrated level after smoothing when no repeater is present, and is a waveform diagram of the combined signal, and (b) is the integrated level after smoothing when the repeater is present. It is a schematic block diagram which shows an example of a smoothing filter. It is drawing which shows an example of the transmission pattern of the signal for a detection. It is drawing which shows the other example of the transmission pattern of the signal for a detection. (A) is drawing which shows the phase change after a synthesis | combination when a repeater is not interposed, (b) is drawing which shows the phase change after a synthesis | combination when a repeater is interposed. (A) is a drawing showing the relationship between the phase change amount and time when no repeater is interposed, and (b) is a drawing showing the relationship between the phase change amount and time when a repeater is interposed. It is a wave form diagram which shows the signal for a detection in a modification. It is a wave form diagram which shows the signal for a detection in a modification.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In the present embodiment, the in-vehicle wireless communication system of the present invention will be described by applying it to an electronic key system mounted on a vehicle.

  As shown in FIG. 1, the in-vehicle wireless communication system (electronic key system) in the present embodiment includes an in-vehicle wireless communication device 100 and a portable device 200. The in-vehicle wireless communication apparatus 100 in this in-vehicle wireless communication system controls the lock / unlock state of the vehicle door when the authorized portable device 200 possessed by the authorized user of the vehicle enters the wireless communication area around the vehicle. It has a function (so-called smart entry function) to execute That is, based on the collation result of the ID code (identification code) by mutual communication between the in-vehicle wireless communication device 100 and the portable device 200, the lock / unlock state of each vehicle door is controlled.

  In response to receiving the request signal, the portable device 200 receives a request signal from the transmitter 20 (for example, a plurality of vehicle interior transmitters or vehicle interior transmitters) of the in-vehicle wireless communication device 100, A transmission unit 202 that transmits a response signal including an ID code or the like within a predetermined range is provided. The transmitting unit 202 radiates radio waves in an RF (Radio Frequency) band as a carrier wave, for example. On the other hand, the transmitter 20 of the in-vehicle wireless communication device 100 radiates, for example, an LF (Low Frequency) radio wave as a carrier wave.

The control unit 203 is connected to the above-described reception unit 201 and transmission unit 202, and executes various control processes. Specifically, the control unit 203 determines whether or not a request signal has been received based on the reception signal of the reception unit 201, or generates a response signal including an ID code in response to the request signal, and transmits the response signal. Or transmitted from the unit 202. Further, the control unit 203 responds to a request signal indicating transmission of a detection signal for detecting whether or not a repeater is interposed between the in-vehicle wireless communication device 100 and the portable device 200, and transmits the transmission unit A plurality of detection signals (signal A and signal B) are transmitted from 202 at a transmission stop interval T _S (corresponding to the transmission interval of the present invention). In other words, the transmission wave-stopping interval T _S is the time to stop the detection signal to be transmitted continuously (OFF).

  As shown in FIG. 4, each detection signal is preferably an analog signal (including an analog high-speed signal or a pulse signal) having a predetermined waveform (amplitude, frequency, frame length T1). That is, it is preferable that the signal A and the signal B are analog signals having the same waveform. However, the present invention is not limited to analog signals.

The transmission wave-stopping interval T _S are those specified by the vehicle wireless communication device 100. Ie contains a signal indicating the transmission wave-stopping interval T _S to a request signal transmitted from the vehicle wireless communication device 100.

  The transmitter 20 of the in-vehicle wireless communication device 100 transmits a request signal within a predetermined range via the transmission antenna 20a based on a transmission instruction signal from a verification ECU (electronic control unit) 10. The reach distance of the request signal of the transmitter 20 (for example, a plurality of vehicle interior transmitters) is set to about 0.7 to 1.0 m, for example. When the vehicle is parked (for example, when all the vehicle doors are closed and all the vehicle doors are locked), a communication area corresponding to the reach distance of the request signal is periodically formed around each vehicle door of the vehicle. It is possible to detect that the holder of the machine 200 has approached the vehicle. The verification ECU 10 outputs a transmission instruction signal based on the detection result of the courtesy switch 80 and the like output from a body ECU (electronic control unit) 60. In addition, a communication area by the transmitter 20 (for example, a vehicle interior transmitter) is also formed so as to cover the vehicle interior when a door lock is operated, and detects whether the portable device 200 is in the vehicle interior. .

  The in-vehicle wireless communication device 100 is provided in the vehicle interior of the vehicle, and is enabled to receive a request signal in synchronization with the output of the request indication signal to the transmitter 20 and receives a response signal transmitted from the portable device 200. A receiver 30 is provided for receiving via the antenna 30a. The response signal received by the receiver 30 is output to the verification ECU 10. The collation ECU 10 collates whether or not the ID code included in the received response signal satisfies a predetermined relationship such as coincidence with a registered code registered in advance. A case where the ID code included in the response signal satisfies a predetermined relationship with a registered code registered in advance is also referred to as verification OK, and a case where the ID code is not satisfied is also referred to as verification NG. The receiver 30 will be described in detail later.

  Then, the verification ECU 10 outputs a control signal to the body ECU 60 in order to control the locked / unlocked state of the door according to whether the verification result is verification OK or verification NG.

  In the in-vehicle wireless communication device 100, the touch sensor 40 is provided on the door handle of each vehicle door of the vehicle, and the holder of the portable device 200 touches the door handle to operate the door handle. It is possible to detect what has been done. The door handle is also provided with a door lock switch 50 (simply described as a lock switch in the drawing) configured as a push switch. When the door lock switch 50 is operated during verification, each vehicle door can be locked. The touch sensor 40 and the door lock switch 50 are connected to the verification ECU 10.

  The body ECU 60 controls the supply and stop of power to each device mounted on the vehicle based on a control signal from the verification ECU 10, and controls the lock / unlock state of each vehicle door. The signal is output to a door lock motor 70 provided at each vehicle door. The door lock motor 70 locks or unlocks the lock mechanism of each vehicle door by rotating forward / reversely based on a drive signal from the body ECU 60. The body ECU 60 is connected to the courtesy switch 80, and can know the locked and unlocked states of the vehicle doors.

  Here, unlock control and lock control of each vehicle door by the in-vehicle wireless communication device 100 will be described.

  For example, when the vehicle engine is stopped and the vehicle is parked with all the vehicle doors closed and locked, the verification ECU 10 transmits the transmitter 20 (for example, a plurality of vehicle interior transmitters) every predetermined time. Is instructed to transmit a request signal, and the transmitter 20 transmits a request signal, thereby confirming whether the holder of the portable device 200 has approached the vehicle. At this time, a request signal indicating transmission of the detection signal is also transmitted.

  When the portable device 200 returns a response signal to the request signal from the transmitter 20, the response signal is received by the receiver 30 of the in-vehicle wireless communication device 100. The verification ECU 10 verifies the ID code as to whether or not the ID code included in the response signal satisfies a predetermined relationship, for example, matches the registered code registered in advance.

  If the verification ECU 10 determines that the verification is OK, the verification ECU 10 outputs a control signal to the body ECU 60. Based on this control signal, the body ECU 60 sets the vehicle door to the unlock standby state.

  When the holder of the portable device 200 touches the door handle of the vehicle door set in the unlock standby state, the operation of the door handle of the holder of the portable device 200 is detected by the touch sensor 40, and the detection signal is the verification ECU 10. Sent to. Then, the verification ECU 10 outputs a control signal to the body ECU 60 in order to unlock the vehicle door. Based on this control signal, the body ECU 60 outputs an unlock driving signal to the door lock motor 70 of each vehicle door to unlock each vehicle door.

  On the other hand, when the vehicle stops and the engine switch is turned off, the holder of the portable device 200 gets off and detects that any one of the door lock switches 50 provided on the door handle is operated. By trying to transmit a request signal using the transmitter 20 (for example, a plurality of vehicle interior transmitters and vehicle interior transmitters), mutual communication with the portable device 200 is attempted. At this time, the response signal is not received in response to the request signal transmitted to the vehicle interior (vehicle interior verification NG), and the response signal is received in response to one of the request signals transmitted to the outside of the vehicle interior. When the ID code verification is OK (outside cabin verification OK), the portable device 200 can be regarded as being outside the cabin. Therefore, since there is no fear that the portable device 200 is trapped in the vehicle interior, the verification ECU 10 outputs a control signal to the body ECU 60 so as to lock the vehicle door. Based on this control signal, the body ECU 60 outputs a lock drive signal to the door lock motor 70 of each vehicle door to lock each vehicle door.

  In the in-vehicle wireless communication device 100, in order to improve the security of the vehicle, when the engine switch is operated, the engine start is permitted / prohibited or the steering lock is disabled according to the ID code collation result. You may make it cancel and maintain. That is, the verification ECU 10 in the in-vehicle wireless communication device 100 is connected to an engine ECU (not shown) that controls the operating state of the engine and a steering lock ECU (not shown) that controls the steering lock state. In response, a control signal may be output. The verification ECU 10 also instructs the engine ECU to set the engine to a start-inhibited state and also instructs the steering lock ECU to lock the steering when the door lock control is executed. .

  Here, the receiver 30 of the in-vehicle wireless communication device 100 will be described with reference to FIGS. 2 and 3. As illustrated in FIG. 2, the receiver 30 includes a reception antenna 30 a that receives a transmission radio wave from the portable device 200, and a response signal (detection signal) transmitted from the portable device 200 among the reception signals from the reception antenna 30 a. A first bandpass filter 32a (hereinafter also referred to as a first BPF 32a) for selectively passing A and the detection signal B), and a first amplifier circuit 33a (amplifying a response signal that has passed through the first BPF 32a) (Hereinafter also referred to as a first AMP 33a), a local oscillator 35 that generates a high-frequency signal with a constant frequency for frequency conversion, and a response signal that is amplified by the first AMP 33a and a high-frequency signal from the local oscillator 35 are mixed to give a command A mixing circuit 34 that converts a signal to a predetermined intermediate frequency band, and a finger that has been converted to an intermediate frequency band by the mixing circuit 34. A second band-pass filter 32b (hereinafter also referred to as a second BPF 32b) that selectively passes a signal, and a second amplifier circuit 33b (hereinafter also referred to as a second AMP 33b) that amplifies the response signal after frequency conversion that has passed through the second BPF 32b. And a demodulation circuit unit 36 that demodulates the response signal amplified by the second AMP 33b. Then, the demodulation circuit unit 36 outputs the demodulated signal to the verification ECU 10. In this way, the receiver 30 demodulates the response signal from the portable device 200 received by the receiving antenna 30a and outputs it to the verification ECU 10.

  Further, the receiver 30 uses a third amplifier circuit 33c (hereinafter also referred to as a third AMP 33c) that amplifies the response signal received by the receiving antenna 30a, and the detection signal amplified by the third AMP 33c. It is determined whether or not a repeater is interposed between the vehicle-mounted wireless communication device 100 and the determination circuit unit 31 that is a characteristic part of the present invention. Then, the determination circuit unit 31 outputs a signal indicating the determination result to the verification ECU 10. The third AMP 33c and the determination circuit unit 31 are integrally provided in the dedicated IC together with the second BPF 32b, the second AMP 33b, and the demodulation circuit unit 36 (that is, the components surrounded by a dotted line in FIG. 2). Concealment can be improved.

Next, the determination circuit unit 31 of the receiver 30 will be described. 3, the determination circuit unit 31 includes an all-pass filter 311 (hereinafter also referred to as APF 311), a smoothing filter 312, a level determination unit 313, a T _S / T _GD value generation unit 314, a random code output unit 315, A T1 value output unit 316 and the like are provided.

The APF 311 corresponds to the delay means of the present invention, and the group delay characteristic T _GD (that is, the time for delaying the detection signal) can be changed. The amplitude and frequency component of the received detection signal are Hold and rotate only the phase 180 degrees. Further, the detection signal passing through the APF 311 is delayed by the group delay characteristic T _GD . Each detection signal passes through both the path that passes through the APF 311 and the path that does not pass. Further, the group delay characteristic T _{GD of the} APF 311 is generated by the T _S · T _GD value generation unit 314, and is set to the same value as the transmission stop interval T _S of the detection signal.

In this embodiment, an example using APF 311 is employed as the delay means of the present invention, but the present invention is not limited to this. Received is rotated 180 degrees phase while maintaining the waveform of the detection signal, as long as it can be delayed by transmission wave-stopping interval T _S and the same time of the detection signal, particular limitation is imposed Absent.

In the subsequent stage of the APF 311, a combining circuit 317 (combining means) that combines a signal that has passed through the APF 311 and a signal that has not passed through the APF 311 is provided. That is, the signal (signal A1) that has passed through the APF 311 of the signal A and the signal (signal B) that has not passed through the APF 311 of the signal B that is transmitted after the transmission stop interval T _S than the signal A are combined.

  The smoothing filter 312 smoothes the amplitude level difference of the synthesized signal synthesized by the synthesis circuit 317 (the subsequent stage of the APF 311). An example of the smoothing filter 312 is shown in FIG. The definition of the smoothing filter is as follows. DIF_out [t] = DIF_out [t-1] + 2-N {DATA [t] -DIF_out [t-1]}. DIF_out [t] is the difference output value after smoothing (initial value is zero). DATA [t] is the differential output level value. N is an integer value (can be set arbitrarily). t is the period for sampling the output differential output level.

  The level determination unit 313 corresponds to a determination unit of the present invention, and determines an integrated level (voltage level) within a predetermined time in the smoothed signal smoothed by the smoothing filter 312. . When the voltage level exceeds a predetermined value, it is determined that a repeater is interposed. When the voltage level does not exceed the predetermined value, it is determined that a repeater is not interposed. Moreover, the signal which shows this determination result is output to collation ECU10.

Note that the T _S · T _GD value generation unit 314 corresponds to a changing unit of the present invention, and generates a signal indicating the transmission stop interval T _S and the group delay characteristic T _{GD of the} APF 311. That is, the T _S · T _GD value generation unit 314 changes the transmission stop interval T _S and the group delay characteristic T _GD (that is, the time for delaying the detection signal). The T _S / T _GD value generation unit 314 generates, for example, a random generation code (for example, 8 bits or more) output from the random code output unit 315 and a frame length T1 output from the T1 value output unit 316. Can do. The group delay characteristic T _GD of the APF 311 can be changed by adopting a digital filter as the APF 311 and changing the coefficient of the digital filter and the number of taps.

T _S · _{T GD} value generating unit 314 outputs the signal indicating the generated transmission wave-stopping interval _{T S} to matching ECU 10, and outputs a signal indicating the generated group delay characteristic _{T GD} to APF311. Signal indicating the group delay characteristic T _GD signal and APF311 indicating the transmission wave-stopping interval T _S is one that is randomly generated for each communication. In other words, collation ECU10 obtaining the signal indicating the transmission wave-stopping interval T _S is changed to a value obtained signal indicating the transmission wave-stopping interval T _S to be included in the next request signal from the T _S · T _GD value generating unit 314 To do. Thus, by changing at random the transmission wave-stopping interval T _S and the group delay characteristics T _GD, it is possible to improve the secrecy. The transmission stop interval T _S (group delay characteristic T _GD ) may be set as appropriate within a range of several μS to several mS.

Furthermore, it is also possible to change the transmission pattern by the transmission wave-stopping interval T _S. That is, for example, as transmission pattern 1 shown in FIG. 10, as the transmission wave-stopping interval _{T S,} when set to the number mS~ number 10 mS, the portable device 200 transmits a signal A responsive to the request signal, After receiving the next request signal, the signal B is transmitted. Further, as the transmission pattern 2 shown in FIG. 11, as the transmission wave-stopping interval T _S, when set to the number μS~ number mS, the portable device 200 transmits a signal A responsive to the request signal, the following The signal B is transmitted before the request signal is received.

The T _S / T _GD value generation unit 314, the random code output unit 315, and the T1 value output unit 316 may be provided in the verification ECU 10. Further, in the present embodiment adopts the example of changing the transmission wave-stopping interval T _S and the group delay characteristics T _GD, the present invention is not limited thereto. Even if you do not change the transmission wave-stopping interval T _S and the group delay characteristics T _GD goal is what can be achieved.

  Here, based on FIG. 3 to FIG. 8, a description will be given of a determination process of whether or not a repeater is interposed.

In response to the request signal indicating transmission of the detection signal transmitted from the in-vehicle wireless communication device 100 (transmitter 20), the portable device 200 receives a plurality of detection signals (signal A, signal B) from the transmission unit 202. transmitted by the transmission wave-stopping interval _{T S.} Here, as shown in FIG. 4, the same waveform (amplitude, frequency, frame length T1) an example of transmitting by the transmission wave-stopping interval T _S between the signal A (dashed line) of the signal B and a (two-dot chain line) adopt.

When the receiver 30 receives the signals A and B transmitted from the transmission unit 202, the signals A and B are input to at least the APF 311. Then, as shown in FIG. 5 (a), the signal passed through the APF311 A1 (dashed line) is delayed with APF311 the group delay characteristic _{T GD} (same as transmission wave-stopping interval _{T S),} with respect to the signal A Thus, the phase is rotated 180 degrees (the signal A that has passed through the APF 311 is described as a signal A1). On the other hand, as shown in FIG. 5B, the phase of the signal B (two-dot chain line) that has not passed through the APF 311 does not change when it is received.

That is, if the repeater between the portable device 200 and the in-vehicle wireless communication device 100 is not interposed, the distance between the signal A and the signal B (that is, while the transmission wave-stopping interval T _S) is maintained. In the subsequent stage of the APF 311, the signal A1 and the signal B are in a state where the phases are rotated (shifted) by 180 degrees. Therefore, the relationship between the signal A1 (one-dot chain line) and the signal B (two-dot chain line) is as shown in FIG. Therefore, the synthesized signal (synthetic wave) of the signal A1 and the signal B has a waveform as shown in FIG.

On the other hand, when a repeater is interposed between the in-vehicle wireless communication device 100 and the portable device 200, the waveform shapes of the signal A and the signal B change, and the interval between the signal A and the signal B is the transmission stop interval. changes from T _S (longer) would be. In the subsequent stage of the APF 311, the signal A1 and the signal B are in a state where the phases are rotated (shifted) by 180 degrees. Therefore, the relationship between the signal A1 (one-dot chain line) and the signal B (two-dot chain line) is as shown in FIG. Therefore, the synthesized signal (synthetic wave) of the signal A1 and the signal B has a waveform as shown in FIG.

  As described above, the waveform of the combined signal is significantly different between the case where the repeater is interposed between the in-vehicle wireless communication device 100 and the portable device 200 and the case where the relay is not interposed.

  Next, the synthesized signal is smoothed by the smoothing filter 312. Then, the level determination unit 313 determines an integrated level (voltage level) within a predetermined time of the signal smoothed by the smoothing filter 312. At this time, the voltage level when no repeater is interposed between the in-vehicle wireless communication device 100 and the portable device 200 is as shown in FIG. On the other hand, the voltage level when a repeater is interposed between the in-vehicle wireless communication device 100 and the portable device 200 is as shown in FIG.

  Then, the level determination unit 313 determines whether or not a repeater is interposed between the in-vehicle wireless communication device 100 and the portable device 200 depending on whether or not the voltage level has reached a predetermined value (threshold value). This threshold value is stored in advance in the storage unit provided in the determination circuit unit 31.

As described above, when the relay between the mobile device 200 and the in-vehicle wireless communication device 100 is not interposed, the signals respectively synthesized (signal A1 and signal B), leaving intervals of the transmission wave-stopping interval T _S Since the phase is rotated by 180 degrees, the voltage level becomes substantially zero when combined, smoothed, and integrated. On the other hand, if the repeater is interposed between the portable device 200 and the in-vehicle wireless communication device 100, the signals respectively synthesized (signal A1 and signal B) varies interval from the transmitting wave-stopping interval T _S, the phase , The voltage level is unlikely to be zero when combined, smoothed, and integrated. Therefore, when the voltage level has reached a predetermined value (threshold value), it is determined that a repeater is interposed, and when it has not reached, it is determined that a repeater is not interposed.

  In this way, it is determined whether or not the in-vehicle wireless communication device 100 and the portable device 200 are directly communicating with each other by using (that is, synthesizing) the entire waveforms of the two detection signals. It is relatively easy to determine whether or not a repeater is interposed between the portable device 200 and the in-vehicle wireless communication device 100, compared to a case where the rising edge or the falling edge such as the above is detected with high accuracy. it can.

  Also, since the synthesized signal is smoothed and the integrated level (voltage level) of the smoothed signal within a predetermined time is determined, it is effective even when the received detection signal is attenuated. .

  Further, as described above, the detection signal is an analog signal (including an analog high-speed signal or a pulse signal) having a predetermined waveform (amplitude, frequency, frame length T1), and is usually portable with the in-vehicle wireless communication device 100. It is different from data signals (for example, wake code, vehicle code, ACK, etc.) used in mutual communication with the machine 200. Therefore, by using this detection signal, it is highly possible that the repeater determines that the detection signal is noise and removes it, thereby improving confidentiality.

  In the present embodiment, an example in which smoothing filter 312 and level determination unit 313 are used to determine whether or not in-vehicle wireless communication device 100 and portable device 200 are directly communicating with each other at a voltage level. However, the present invention is particularly limited as long as it determines whether or not the in-vehicle wireless communication device 100 and the portable device 200 are directly communicating with each other at the voltage level using the combined signal. It is not a thing. Therefore, when the determination is not made based on the voltage level, the smoothing filter 312 and the level determination unit 313 may not be provided.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the embodiment mentioned above at all, and various deformation | transformation are possible in the range which does not deviate from the meaning of this invention.

  In the above-described embodiment, the example of using the integrated level (voltage level) is adopted as the method for determining the synthesized wave (synthesized signal), but the present invention is not limited to this. For example, a method of calculating the phase change amount in the combined wave and comparing the phase change amounts may be employed. As described above, the combined signal is different depending on whether or not the repeater is interposed (see FIGS. 7A and 7B). That is, as shown in FIG. 12, the amount of change in phase is different. Therefore, as shown in FIG. 13 (a), the amount of phase change after combining (combined signal) is calculated, and when the amount of phase change is less than a preset threshold, a repeater is interposed. As shown in FIG. 13 (b), if the amount of phase change after synthesis (synthesized signal) is greater than or equal to a preset threshold, the repeater is interposed. Determine (determination means). Even if it does in this way, there can exist an effect similar to the above-mentioned.

In the above-described embodiment, an example in which a detection signal is transmitted in the RF band is employed, but the present invention is not limited to this. For example, the detection signal may be transmitted in the LF band. Also in this case, the same waveform (amplitude, frequency, frame length T1) a plurality of detection signals having the (signal A, signal B) is transmitted at a transmission wave-stopping interval T _S.
Note that signal components (FSK, pulse signals, etc.) having a wideband signal component transmitted in the LF band are not appropriate because they are attenuated due to the characteristics of the receiving antenna. Therefore, it is preferable to employ a CW (continuous wave) wave having a constant frequency as shown in FIG. 14 or a PSK (phase shift keying) modulated wave as shown in FIG. 15 as the detection signal.

Also, when changing the transmission pattern by the transmission wave-stopping interval _{T S,} for example, it is the number 10μs~ several ms as the transmission pattern 3, also possible to employ the number ms~ number 10ms as transmission pattern 4.

10 collation ECU, 20 transmitter, 30 receiver, 31 determination circuit unit, 311 all-pass filter, 312 smoothing filter, 313 level determination unit, 314 T _S / T _GD value generation unit, 315 random code output unit, 316 T1 value Output unit, 317 synthesis circuit, 40 touch sensor, 50 lock switch, 60 body ECU, 70 door lock motor, 80 courtesy switch, 100 in-vehicle wireless communication device, 200 portable device, 201 reception unit, 202 transmission unit, 203 control unit

Claims (5)

In response to a request signal transmitted within a predetermined range from an in-vehicle wireless communication device provided in the vehicle, the portable device performs mutual communication in which a response signal including an identification code is returned within the predetermined range. The in-vehicle wireless communication device receives the response signal from the portable device, collates the identification code included in the response signal with a registered code registered in advance, and locks and unlocks the vehicle door according to the collation result In-vehicle wireless communication system for controlling
The in-vehicle wireless communication device transmits, as the request signal, a signal requesting to return a detection signal having a predetermined waveform at a predetermined transmission interval,
In response to the signal, the portable device returns a detection signal having a predetermined waveform at a predetermined transmission interval,
The in-vehicle wireless communication device is
A delay means for rotating the phase by 180 degrees while retaining the waveform of the received detection signal, and delaying the detection signal by the same time as the transmission interval;
Combining means for combining the detection signal delayed by the delay means and the detection signal that is returned with a transmission interval to the detection signal and not delayed by the delay means;
A determination unit that determines whether or not the in-vehicle wireless communication device and the portable device directly perform mutual communication using the combined signal combined by the combining unit;
An in-vehicle wireless communication system comprising:   The determination unit smoothes the synthesized signal synthesized by the synthesizing unit, integrates the smoothed smoothed signal, compares the integrated value with a predetermined value, and the integrated value exceeds a predetermined value Determines that the in-vehicle wireless communication device and the portable device are not directly communicating with each other, and if the predetermined value is not exceeded, the in-vehicle wireless communication device and the portable device are directly communicating with each other. The in-vehicle wireless communication system according to claim 1, wherein the in-vehicle wireless communication system is determined.   The determination unit calculates a phase change amount in the synthesized signal synthesized by the synthesis unit, compares the phase change amount with a predetermined value, and if the phase change amount exceeds a predetermined value, the vehicle-mounted radio It is determined that the communication device and the portable device are not directly communicating with each other, and if the predetermined value is not exceeded, it is determined that the in-vehicle wireless communication device and the portable device are directly performing mutual communication. The in-vehicle wireless communication system according to claim 1.   The in-vehicle wireless communication system according to claim 1, wherein the delay unit includes an all-pass filter.   5. The in-vehicle wireless communication system according to claim 1, wherein the in-vehicle wireless communication apparatus includes a changing unit that changes the transmission interval and a time for delaying the detection signal.

Images