TRANSFER TAX DEVICE

Abstract

Transmission control device used in an authentication system (1) which enables the control of an authentication target based on authentication established by verification via wireless communication between the authentication target and a portable device (2) worn by a user, comprising: an antenna driver unit (303) configured to output a driver current to a transmission antenna (31) to cause the transmission antenna (31) to transmit a signal with a specified frequency band; a current setting unit (306) configured to set the driver current output by the antenna driver unit (303); a monitoring unit (304) configured to detect a current flowing through the transmission antenna (31); and a correction value determination unit (307) configured to determine a correction value of the driver current output by the antenna driver unit (303) by feedback control based on the current detected by the monitoring unit (304), wherein After the correction value determination unit (307) determines the correction value, the current setting unit (306) corrects the driver current in order to transmit a request signal as the signal which is used for verification based on the correction value, characterized in that the correction value determination unit (307) determines the correction value of the driver current in order to transmit a test signal output by the antenna driver unit (303) as a test through the feedback control based on the current detected by the monitoring unit (304); and the test signal differs from the request signal.

Description

Reference to related registration

[0001] This application is based on Japanese patent application no. 2017-210208 filed on October 31, 2017; full reference is made here to the disclosure content contained therein. Technical field

[0002] The present disclosure relates to a transmission control device. State of the art

[0003] Conventionally, an authentication system has been proposed that enables the control of an authentication target based on authentication established through verification between the authentication target and a portable device via wireless communication. For example, JP 2010-185 186 A discloses an authentication system that performs verification between a vehicle device and a portable device via wireless communication to lock and unlock a vehicle door. Furthermore, JP 2010-185 186 A discloses a technique in which, to reduce unauthorized unlocking by a relay attack, the change in intensity of a request signal transmitted by a vehicle transmission antenna is controlled, and the portable device detects the presence or absence of this change in the request signal's intensity.US 2008 / 0085733A1 relates to an antenna device that forms an arrival area for a transmit request signal sent to detect the presence of the portable device. Summary of the invention

[0004] In order to implement a technique disclosed in JP 2010 - 185 186 A, it is desirable to transmit a request signal with the intended intensity precisely.

[0005] In view of the difficulties described above, an object of the present disclosure is to provide a transmission control device that enables the precise output of a request signal with a desired intensity in an authentication system. This system allows the control of an authentication target based on authentication established by verification, via wireless communication between the authentication target and a portable device. This object is achieved by the subject matter of independent claims 1, 4, and 5. Further developments of the invention are the subject of the dependent claims.

[0006] According to one aspect of the present disclosure, a transmission control device is used in an authentication system. The authentication system enables the control of an authentication target based on authentication established by verification via wireless communication between the authentication target and a portable device worn by a user. The transmission control device comprises an antenna driver unit, a current setting unit, a monitoring unit, and a correction value determination unit. The antenna driver unit is configured to output a driver current to a transmission antenna to cause the transmission antenna to transmit a signal within a predetermined frequency band. The current setting unit is configured to adjust the driver current output by the antenna driver unit.The monitoring unit is configured to detect the current flowing through the transmission antenna. The correction value determination unit is configured to determine a correction value for the driver current through feedback control based on the current detected by the monitoring unit. After the correction value determination unit determines the correction value, the current adjustment unit corrects the driver current to transmit a request signal, which is used for verification based on the correction value.

[0007] The transmission control device determines the correction value of the driver current through the antenna driver unit via feedback control, based on the current detected by the monitoring unit. This allows the transmission control device to precisely adjust the current flowing through the transmission antenna to the setpoint. Once the correction value is determined, the driver current is adjusted to transmit the request signal, which is used for verification, based on this correction value. Thus, the transmission control device can precisely adjust the current flowing through the transmission antenna to the setpoint and output the request signal with the exact intended intensity.As a result, in the authentication system, which enables the control of the authentication target based on establishing authentication through verification via wireless communication between the authentication target and the portable device, the request signal can be output with the precise intended intensity. Brief description of the drawings

[0008] The objects, features, and advantages described above, as well as other objects, characteristics, and benefits of the present disclosure, will become clearer from the following detailed description in relation to the accompanying drawings. In the drawings: Fig. Figure 1 is a diagram showing an example of a schematic configuration of an authentication system; Fig. Figure 2 is a diagram showing an example of a schematic configuration of a vehicle unit and a BCM; Fig. Figure 3 is a diagram showing an example of the determination of a correction value of a driver current by a correction value determination unit; Fig. 4 is a flowchart that shows an example of the correction value determination process in the BCM; Fig. 5 is a flowchart that shows an example of a correction value determination processing process in the BCM; Fig. 6 is a flowchart showing an example of the correction value determination processing process in the BCM; and Fig. Figure 7 is a diagram showing an example of the determination of the driver current correction value by the correction value determination unit. Examples of embodiments for carrying out the invention

[0009] Several embodiments are described below as disclosures with reference to the drawings. To simplify the description, sections with the same functions as those in the drawings used so far in the description are assigned the same reference numerals under the majority of embodiments, and a description of the same sections can be omitted. Reference can be made to the description in another applicable embodiment for such a section, which is identified by the identical reference numeral. (First Implementation Example)(Authentication System 1)

[0010] The first embodiment of the present disclosure is described with reference to the drawings. Fig. Figure 1 is a diagram showing a schematic configuration of an authentication system 1. The one in Fig. 1 The authentication system 1 shown comprises a portable device 2 worn by a user and a vehicle unit 3 mounted on a vehicle.

[0011] Authentication system 1 has a so-called smart function. This smart function performs authentication by verifying the connection between the portable device 2 and the vehicle unit 3 via wireless communication and enables control of the vehicle as an authentication target once authentication is established. Controlling the vehicle, enabled by authentication, can include locking and unlocking a door and starting a drive power source.

[0012] The mobile device 2 functions as an electronic key. The mobile device 2 can be provided by a fob, a multifunctional mobile phone with electronic key functionality, or the like. The portable device 2 receives a request signal transmitted by the vehicle unit 3 on a radio wave of an LF band (low frequency) via a receiving antenna. The LF band is a low frequency band, for example, from 30 kHz to 300 kHz. In this embodiment, the request signal is a signal for requesting the transmission of a verification code and is a signal used for verification.When a challenge-response system is used, the request signal corresponds to a challenge signal, and the signal to request a transmission corresponds to an encrypted code in which the code of the challenge signal is encrypted by a secret key and an encryption algorithm used in a common key encryption system.

[0013] Furthermore, when portable device 2 receives the request signal, it transmits a response signal containing a verification code over a radio wave in an RF band (radio frequency band) from the transmission antenna. The RF band is a high-frequency band, for example, from 300 Hz to 3 THz. If the request signal contains a verification code on portable device 2, one condition for responding to the response signal from portable device 2 is to establish code verification using that code. Additionally, to mitigate the risk of a relay attack, the condition for responding to the response signal in portable device 2 may include fulfilling a change in the output of the request signal, which is controlled according to predefined logic at the vehicle unit 3. (Vehicle unit 3)

[0014] With reference to Fig. Section 2 describes an example of a schematic configuration of vehicle unit 3. As in Fig. As shown in Figure 2, the vehicle unit 3 comprises a BCM (onboard power supply control unit) 30, an LF antenna 31, an RF receiver 32, a DS door handle switch 33, a PS door handle switch 34, a rear bumper switch 35, and a pressure switch 36. Hereinafter, the switch is referred to as SW.

[0015] The LF antenna 31 is a transmission antenna that transmits a signal on the radio wave of the LF band. Several LF antennas 31 can be provided in the vehicle. For example, the LF antennas 31 can be located near a driver's seat door (DS), near a passenger seat (PS), near a trunk door, in a vehicle compartment, and the like. The RF receiver 32 receives the response signal from the portable device 2 on the radio wave of the RF band.

[0016] The OS door handle SW 33 is a switch located on an outer door handle of the driver's seat in the vehicle. The PS door handle SW 34 is a switch located on an outer door handle of the passenger seat in the vehicle. The rear bumper SW 35 is a switch located on the rear bumper of the vehicle. The pressure SW 36 is a switch located in the front area of ​​the driver's seat to request the start of a propulsion source in the vehicle.

[0017] The BCM 30 comprises a processor, memory, I / O, and a bus connecting these components. It performs various processes related to authentication within the vehicle by executing a control program stored in memory. The memory referred to here is a non-permanent physical storage medium configured to temporarily store a program and data readable by a computer. This non-permanent physical storage medium is either a semiconductor memory or a magnetic disk. (BCM 30)

[0018] In relation to Fig. Section 2 describes an example of a schematic configuration of the BCM 30. As in Fig. As shown in Figure 2, the BCM 30 comprises an LF driver IC 300, a DCDC circuit 310, a LIN driver 320, a CAN driver 330, a SW input circuit 340, and a microcomputer 350. CAN is a registered trademark.

[0019] The BCM 30 is connected to a CAN bus, which is a transmission path for communication using CAN as a communication protocol, and a LIN bus, which is also a transmission path for communication using LIN as a communication protocol. The LIN bus is the transmission path through which the BCM 30 exchanges information with an actuator such as a door lock motor, a vehicle light, the RF receiver 32, or similar device. The CAN bus is the transmission path through which the BCM 30 exchanges information with another electronic control unit, such as a powertrain control unit (ECU) that controls the vehicle's drive system.

[0020] The DC-DC converter 310 is a circuit that supplies a DC voltage to the LF driver IC 300. The LIN driver 320 outputs information to the LIN bus and receives information from the LIN bus. The LIN driver 320 receives a code for the response signal received by the RF receiver 32 from the RF receiver 32. The LIN driver 320 outputs the received information to the microcomputer 350. Additionally, the LIN driver 320 outputs a driver signal to the door locking motor, which is then output by the microcomputer 350 to control the locking and unlocking of the vehicle door.

[0021] The CAN driver 330 outputs information to and receives information from the CAN bus. The CAN driver 330 outputs a start authorization signal, which is then sent by the microcomputer 350 to the powertrain control unit (ECU). The CAN driver 330 also receives a vehicle status reading, such as vehicle speed output by another ECU, and sends this reading to the microcomputer 350.

[0022] The SW input circuit 340 is a circuit into which the signals transmitted by the DS door handle SW33, the PS door handle SW34, the rear bumper SW35 and the pressure SW36 are input, and transmits the input signals to the microcomputer 350.

[0023] As in Fig. As shown in Figure 2, the microcomputer 350 has the following functional blocks: a LIN interface 351, a CAN interface 352, a microcomputer communication interface 353, a software input interface 354, a vehicle status determination unit 355, a request unit 356, a registration unit 357, and a verification unit 358. Hereinafter, the interface is referred to as an IF.

[0024] The LIN-IF 351 is an interface for communication between the LIN driver 320 and the microcomputer 350. The CAN-IF 352 is an interface for communication between the CAN driver 330 and the microcomputer 350. The microcomputer communication-IF 353 is an interface for serial communication between the microcomputer 350 and the LF driver IC 300. The SW input-IF 354 is an interface for communication between the SW input circuit 340 and the microcomputer 350.

[0025] The vehicle state determination unit 355 determines the vehicle's state based on the vehicle state data acquired by the CAN driver 330 via the CAN interface 352. For example, the vehicle state determination unit 355 determines whether the vehicle is parked or moving, based on vehicle speed detected by a vehicle speed sensor, gear position detected by a gear position sensor, a signal from a parking brake switch, or similar information.

[0026] The request unit 356 requests the LF driver IC 300 to transmit the request signal or to correct the current of the LF antenna 31 via microcomputer communication IF 353 based on the signal received by the SW input circuit 340 and the vehicle state determined by the vehicle state determination unit 355. The processes performed by the request unit 356 are described in more detail later.

[0027] The registration unit 357 can be provided by electrically rewritable non-volatile memory and store information for authentication. The authentication information can be provided by a code from an original portable device 2 or the secret key used in the shared key encryption system when the request-response system is used.

[0028] The verification unit 358 compares the code of the response signal, which is captured by the RF receiver 32 via the LIN-IF 351, and the original code using the authentication information stored in the registration unit 357. If the authentication information is the code of the original portable device 2, the verification unit 358 compares the code of the response signal and the code of the original portable device 2. If the prompt-response method is used, the verification unit 358 compares the encrypted code of the response signal captured by the RF receiver 32 and the encrypted code obtained by encrypting the prompt signal transmitted by the LF antenna 31 using the secret key stored in the registration unit 357.

[0029] When the verification unit 358 performs the verification with the portable device 2 outside the vehicle compartment (hereinafter referred to as external verification) and authentication is established, the driver signal for controlling the locking and unlocking of the vehicle door is transmitted to the door locking motor via the LIN-IF 351 and the LIN driver 320, and the locking and unlocking of the vehicle door is performed. When the external verification is performed and authentication is established, the verification unit 358 transmits the driver signal to switch on the light as a welcome function driver to a light such as the small lamp, the interior light, or the like via the LIN-IF 351 and the LIN driver 320, causing the light to switch on automatically.

[0030] When the verification unit 358 performs the verification with the portable device 2 inside the vehicle compartment (hereinafter referred to as internal verification) and authentication is established, the verification unit 358 transmits the start authorization signal to the drive unit ECU via the CAN interface 352 and the CAN driver 330, causing the vehicle's drive source to be activated. For example, when the RF receiver 32 receives a response to a signal transmitted by the LF antenna 31, whose communication range is limited to the interior of the vehicle compartment, the verification unit 358 determines that the internal verification has been established.For example, if the response to a signal transmitted by the LF antenna 31, whose communication range is limited to the interior of the vehicle compartment, is not received, but a response to a signal transmitted by the LF antenna 31, whose communication range extends outside the vehicle compartment, is received, the verification unit 358 determines that the external verification has been established.

[0031] The LF driver IC 300 is an integrated circuit (IC) that transmits a signal from the LF antenna 31. The LF driver IC 300 and the BCM 30, including the LF driver IC 300, constitute a transmission control device. The LF driver IC 300 transmits the request signal from the LF antenna 31 according to a request from the microcomputer 350. Furthermore, the LF driver IC 300 determines the correction value of the driver current for transmitting a signal to be output to the LF antenna 31, according to the current correction request from the microcomputer 350, and corrects the driver current. A detailed configuration of the LF driver IC 300 is described below. (LF driver IC 300)

[0032] In relation to Fig. Section 2 describes an example of a schematic configuration of the LF driver IC 300. As in Fig. As shown in Figure 2, the LF driver IC 300 comprises as functional blocks a DCDC converter 301, an IC communication IF 302, an LF driver 303, an LF control unit 305 and an output setting memory unit 308.

[0033] The DC-DC converter 301 converts a DC voltage input from the DC-DC circuit 310 into a power supply voltage required for the operation of the LF driver IC 300. The IC communication interface 302 is an interface for serial communication between the LF driver IC 300 and the microcomputer 350.

[0034] The LF driver 303 outputs the driver current to transmit a signal to the LF antenna 31 based on the control of the LF control unit 305. The LF driver 303 is an antenna driver unit. The LF driver 303 has a monitoring unit 304 and detects the current flowing through the LF antenna 31. The monitoring unit 304 can detect the current flowing through the LF antenna 31 by means of a current sensing circuit. Alternatively, the monitoring unit 304 can detect the current flowing through the LF antenna 31 by measuring a voltage across the LF antenna 31 and converting the measured voltage.

[0035] The LF control unit 305 controls the LF driver 303 to output the driver current for transmitting a signal to the LF antenna 31, so that the LF antenna 31 transmits a signal. When a transmission request of the request signal is received from the microcomputer 350 via the IC communication interface 302, the LF control unit 305 causes the LF driver 303 to output the driver current for transmitting the request signal to the LF antenna 31. In this configuration, the request signal is transmitted by the LF antenna 31. The LF control unit 305 can change the intensity of the request signal according to a predefined logic.

[0036] The LF control unit 305 comprises a current setting unit 306 and a correction value determination unit 307. The current setting unit 306 sets the driver current output by the LF driver 303. When a request to correct the current is received from the microcomputer 350 via the IC communication interface 302, the correction value determination unit 307 determines the correction value of the driver current output by the LF driver 303 by feedback control based on the current detected by the monitoring unit 304. The correction value determination unit 307 stores the determined correction value in the output setting memory unit 308. The output setting memory unit 308 can be provided by an electrically rewritable memory.After the correction value determination unit 307 has determined the correction value, the current setting unit 306 corrects the driver current for transmitting the request signal, so that the intensity of the request signal is a setpoint based on the correction value stored in the output setting memory unit 308.

[0037] Here, the determination of the correction value of the driver current by the correction value determination unit 307 is described in relation to the Fig. 3 described in more detail. Fig. Figure 3 is a diagram showing the change over time of a current flowing through the LF antenna 31. Fig. 3 The vertical axis represents the current and the horizontal axis represents time.

[0038] The correction value determination unit 307 determines the correction value of the driver current by means of feedback control, such that the current flowing through the LF antenna 31 is the setpoint. For example, the correction value determination unit 307 calculates the difference between the driver current output by the LF driver 303 and the correction target based on shifts in phase and amplitude. While adjusting the driver current to eliminate the difference, the correction value determination unit 307 performs feedback control until the current flowing through the LF antenna 31 is the correction setpoint. Then, the correction value determination unit 307 determines the value of the driver current as the correction value when the current flowing through the LF antenna 31 is the correction setpoint. This process corresponds to one current correction period in Fig. 3. Furthermore, the correction value determination unit 307 stores the determined correction value in the output setting memory unit 308.

[0039] When the request signal is transmitted from the LF antenna 31, the current setting unit 306 corrects the driver current for transmitting the request signal so that the current flowing through the LF antenna 31 is the setpoint based on the correction value stored in the output setting memory unit 308. The current setting unit 306 then transmits the request signal from the LF antenna 31. As described in Fig. As shown in Figure 3, the correction value can differ from the setpoint of the current when the request signal is transmitted. In this case, the request signal is corrected so that the driver current value corresponds to the setpoint of the current when the request signal is transmitted. The correction is performed based on a ratio of the correction value stored in the output setting memory unit 308 and the correction target value of the current flowing through the LF antenna 31. For example, the correction value can be set to 500 mA as the correction target, and 1 A as the setpoint. In this case, the driver current is corrected to 1 A based on the ratio of the correction value to 500 mA and the setpoint value.If the correction value is the same as the setpoint of the current when the request signal is transmitted, the correction value stored in the output setting memory unit 308 can be used without the correction.

[0040] When the correction value determination unit 307 determines the correction value by the feedback control during the transmission of the request signal, the responsiveness deteriorates until the current flowing through the LF antenna 31 reaches the setpoint. If, in addition, the intensity of the request signal is high, the noise increases due to overshoot, as shown by a dashed circle in Fig. 3 shown. Therefore, determined as in Fig. Figure 3 shows the correction value determination unit 307 determining the correction value in a signal (hereinafter referred to as a test signal) which is to be transmitted as a test before the transmission of the request signal by the feedback control based on the current detected by the monitoring unit 304 in relation to the driver current output by the LF driver 303 to the LF antenna 31.

[0041] Additionally, in a signal containing data such as a request signal, the current value changes significantly to represent two values ​​of "1" and "0". Therefore, determining the correction value by the feedback control is difficult. Consequently, the correction value is determined by the feedback control using the test signal, in which the current value does not contain the data and is continuous. The correction value determination unit 307 can be performed by the microcomputer 350 according to a current correction request. Some specific examples of times at which the correction value determination unit 307 determines the correction value are described below. (Correction value determination processing in BCM 30)

[0042] Here are examples of processing flows relating to determining the correction value of the driver current for transmitting the request signal in the BCM 30 (hereinafter referred to as correction value determination processing), in relation to the flowcharts of the Fig. 4 to 6 described.

[0043] For example, the point in time at which the correction value determination unit 307 determines the correction value could be the point in time at which the BCM 30 is connected to the vehicle's battery and activated for the first time. The flowchart in Fig. Figure 4 is a diagram showing an example of the correction value determination process when the correction value is determined at the time the BCM 30 is connected to the vehicle's battery and activated for the first time. The flowchart of Fig. 4 starts when the BCM 30 is connected to the vehicle's battery.

[0044] First, in S1, the microcomputer 350 begins initializing its power. In S2, the request unit 356 of the microcomputer 350 requests the LF driver IC 300 to correct the current. In S3, the LF control unit 305 of the LF driver IC 300 causes the LF driver 303 to transmit the test signal and determines the correction value by feedback control based on the current detected by the monitoring unit 304 relative to the driver current output by the LF driver 303. The determined correction value is then stored in the output setting memory unit 308, and the correction value determination process is terminated. At the time of subsequent transmission of the request signal, the driver current can be corrected for transmitting the request signal using the correction value.

[0045] Even when the BCM 30 is connected to the vehicle's battery and activated for the first time before the transmission of the request signal from the LF antenna 31, the correction value of the driver current can be determined by the feedback control described above, and the correction value for precisely adjusting the current flowing through the antenna 31 to the setpoint can be stored in the output setting memory unit 308. Therefore, even if the LF antenna 31 and the BCM 30 vary from unit to unit during installation on the vehicle, the driver current for transmitting the request signal can be corrected using the correction value, and the request signal can be transmitted with the precise intended intensity.

[0046] Another example of when the correction value determination unit 307 determines the correction value could be when the vehicle is parked and the vehicle interior verification is complete. The flowchart in Fig. Figure 5 is a diagram that shows an example of the correction value determination process flow when the correction value is determined in a case where the vehicle is parked and the vehicle interior verification is complete. The flowchart in Fig. 5 can start when, for example, the vehicle status determination unit 355 determines that the vehicle is parked, and a signal indicating that pressure SW 36 has been actuated is entered into the BCM 30.

[0047] First, in S21, the request unit 356 of the microcomputer 350 requests the LF driver IC 300 to transmit the request signal, and the LF driver IC 300 causes the LF antenna 31 to transmit the request signal.

[0048] If the vehicle interior verification is successful in S22 by the verification unit 358, processing proceeds to S23. If, however, the vehicle interior verification is not successful by the verification unit 358, processing returns to S21 and repeats the process. In S23, the verification unit 358 outputs the start authorization signal to the powertrain ECU and starts the vehicle's drive power source.

[0049] In S24, the request unit 356 of the microcomputer 350 requests the LF driver IC 300 to correct the current. In S25, the LF control unit 305 of the LF driver IC 300 causes the LF driver 303 to transmit the test signal and determines the correction value by feedback control based on the current detected by the monitoring unit 304 with respect to the driver current output by the LF driver 303. The determined correction value is then stored in the output setting memory unit 308, and the correction value determination processing is terminated. At the time of subsequent transmission of the request signal, the driver current for transmitting the request signal can be corrected using the correction value.

[0050] Each time the vehicle interior verification is completed while the vehicle is parked, the correction value is determined by the feedback control described above. Accordingly, even under the influence of temperature, aging, or similar factors, the request signal can be issued with the precise intended intensity.

[0051] Another example of when the correction value determination unit 307 determines the correction value could be when the vehicle is moving. The flowchart in Fig. Figure 6 is a diagram showing an example of the correction value determination process when the correction value is determined in a case where the vehicle is moving. The flowchart in Fig. 6 can start if, for example, the vehicle state determination unit 355 determines that the vehicle is moving. In Fig. Section 6 describes an example in which vehicle interior verification is performed periodically while the vehicle is in motion to prevent the vehicle from being removed due to a relay attack by a third party. In the relay attack, the third party indirectly establishes wireless communication between the BCM 30 and the portable device 2 by relaying the request signal from the LF antenna 31 over a long distance using a relay device to illegally establish authentication.

[0052] In S41, if an AM (amplitude modulation) radio is used, transmitting on the medium wave band using amplitude modulation, processing proceeds to S46. If, however, the AM radio is not used, processing proceeds to S42. Whether the AM radio is in use or not can be determined by the vehicle state determination unit 355 via the CAN driver 330 and the CAN interface 352, which receive a signal relating to the operation of a receiver of the vehicle-mounted AM radio.

[0053] In S42, the request unit 356 of the microcomputer 350 periodically requests the LF driver IC 300 to transmit the request signal, and the LF driver IC 300 periodically causes the LF antenna 31 to transmit the request signal. The term "periodic" used here refers to a time interval that can be arbitrarily defined and can, for example, be several minutes.

[0054] If the vehicle interior verification is successfully completed by verification unit 358 in S43, processing proceeds to S44. Conversely, if the vehicle interior verification is not completed by verification unit 358, processing returns to S41 and repeats the process. If the vehicle interior verification is not completed in S43, the vehicle may be stopped or similar measures taken to prevent it from being removed due to the relay attack.

[0055] In S44, the request unit 356 of the microcomputer 350 requests the LF driver IC 300 to correct the current. In S45, the LF control unit 305 of the LF driver IC 300 causes the LF driver 303 to transmit the test signal and determines the correction value by feedback control based on the current detected by the monitoring unit 304 with respect to the driver current output by the LF driver 303. The correction value determination unit 307 stores the determined correction value in the output setting memory unit 308. At the time of subsequent transmission of the request signal, the driver current for transmitting the request signal can be corrected using the correction value.

[0056] In S46, the correction value determination processing is terminated when the end time of the correction value determination processing is reached. If, however, it is not the end time of the correction value determination processing, the processing returns to S41 to repeat the process. The end time of the correction value determination processing, which is referenced here, includes, for example, when the vehicle's ignition power is switched off.

[0057] When the vehicle is in motion, the correction value is periodically determined by the feedback control described above. Accordingly, even under the influence of temperature, aging, or similar factors, the request signal can be output with the precise intended intensity.

[0058] When AM radio is used, the request signal or test signal may not be transmitted to prevent AM radio noise from overlapping the AM band of the LF band used to transmit the signal from LF antenna 31. However, the configuration is not limited to this. Unlike AM radio, if, for example, a vehicle-mounted radio is used that operates on a frequency band overlapping with the frequency band used to transmit the request or test signal, the request or test signal may not be transmitted.

[0059] The in the Fig. The correction value determination processes shown in sections 4 to 6 can be performed together or partially. Furthermore, the point in time at which the correction value determination unit 307 determines the correction value is not limited to those shown in the Fig. Figures 4 to 6 are shown. For example, when the vehicle is moving, the correction value determination unit 307 can determine the correction value without performing the vehicle interior verification. Furthermore, the correction value determination unit 307 can determine the correction value when the vehicle is parked and the operation of the drive source is switched from ON to OFF.

[0060] Additionally, during the query period, in which the LF antenna 31 intermittently transmits the request signal from the vehicle exterior verification after exiting the vehicle to the vehicle exterior verification before exiting the vehicle, the test signal is transmitted, and the correction value determination unit 307 can determine the correction value. Determining the correction value can be performed less frequently than transmitting the request signal during the query period. For example, the correction value can be determined only once. This is because if the vehicle's parking position does not change, there is a high probability that the ambient temperature will not change significantly. To enable a more precise output of the request signal with the intended intensity, taking into account the temperature difference between day and night, the correction value can be determined more than once.

[0061] When the request signal is transmitted, the correction value determination unit 307 can determine the correction value for the request signal by performing feedback control on the driver current output by the LF driver 303 based on the current detected by the monitoring unit 304. In this case, if the request signal is transmitted at a specific time, the correction value is determined by the feedback control. If the request signal is transmitted subsequently, the driver current for transmitting the request signal can be corrected using the correction value stored in the output setting memory unit 308.

[0062] In the first embodiment, the correction value of the driver current output by the LF driver 303 is determined by the feedback control based on the current detected by the monitoring unit 304. Thus, the configuration can determine the correction value to precisely adjust the current flowing through the LF antenna 31 to the setpoint. After the correction value is determined, the driver current is corrected based on the correction value to transmit the request signal used for verification. Therefore, the configuration can precisely adjust the current flowing through the LF antenna 31 to the setpoint and output the request signal with the precise intended intensity.As a result, in the authentication system 1, which enables the control of the vehicle based on establishing authentication through verification via wireless communication between the vehicle and the portable device 2, the request signal can be output with the precise intended intensity. (Second example)

[0063] Furthermore, the correction value determination unit 307 can transmit the previously described test signal several times by causing the LF driver 303 to output the driver current several times, which is set to the same value by the current setting unit 306. The correction value determination unit 307 then calculates, as described in Fig. Figure 7 shows the correction values ​​(the correction values ​​α, β, γ in Fig.7) for the multiple times by the feedback control to the driver current output by the LF driver 303, based on the current detected by the monitoring unit 304. The correction value determination unit 307 can determine the correction value by averaging the calculated correction values ​​for the driver current. Thus, the configuration can determine the correction value more precisely and output the request signal with the more precise intended intensity. (Third embodiment)

[0064] The previously described embodiment describes the configuration in which authentication system 1 is applied to a vehicle. However, authentication system 1 can be applied to an object other than a vehicle. For example, the configuration can be applied to a house, a facility, or the like to authenticate the locking and unlocking of the house, facility, or the like door.

[0065] A flowchart or process of the flowchart described in the present disclosure contains several parts (or steps), and each part is expressed, for example, as S1. Furthermore, each part can be subdivided into several subparts, while the several parts can be combined into one part.

[0066] Each of these sections can also be referred to as a circuit, device, module, or means.

[0067] Each of the multiple sections, or some of the sections combined together, can be configured as (i) a software section in combination with a hardware unit (e.g., a computer), or (ii) a hardware section (e.g., an integrated circuit or a wiring logic circuit) that includes or excludes a function of a relevant device. Alternatively, the hardware section can be installed in a microcomputer.

[0068] It should be noted that the present disclosure is not limited to the embodiments described above and can be modified in various ways within the scope of the claims. An embodiment obtained by a suitable combination of the technical means disclosed in the various embodiments is also included within the technical scope of the present disclosure.

Claims

[1] Transmission control device used in an authentication system (1) which enables the control of an authentication target based on authentication established by verification via wireless communication between the authentication target and a portable device (2) worn by a user, comprising: an antenna driver unit (303) configured to output a driver current to a transmission antenna (31) to cause the transmission antenna (31) to transmit a signal with a specified frequency band; a current setting unit (306) configured to set the driver current output by the antenna driver unit (303); a monitoring unit (304) configured to detect a current flowing through the transmission antenna (31); and a correction value determination unit (307) configured to determine a correction value of the driver current output by the antenna driver unit (303) by feedback control based on the current detected by the monitoring unit (304), wherein After the correction value determination unit (307) determines the correction value, the current setting unit (306) corrects the driver current to transmit a request signal as the signal, which is used for verification based on the correction value, characterized by , that the correction value determination unit (307) determines the correction value of the driver current in order to transmit a test signal output by the antenna driver unit (303) as a test through the feedback control based on the current detected by the monitoring unit (304); and the test signal differs from the request signal. [2] Transmission control device according to claim 1, wherein: the authentication target is provided by a vehicle; the transmission control device is mounted on the vehicle; and The correction value determination unit (307) determines the correction value by causing the antenna driver unit (303) to output the driver current to transmit the test signal and the transmission antenna (31) to transmit the test signal when the transmission control device is connected to a battery and activated for the first time. [3] Transmission control device according to claim 1 or 2, wherein: the authentication target is provided by a vehicle; the transmission control device is mounted on the vehicle; and The correction value determination unit (307) determines the correction value by causing the antenna driver unit (303) to output the driver current to transmit the signal and the transmission antenna (31) to transmit the signal when the vehicle is parked and after verification is carried out with the portable device (2) in a passenger compartment of the vehicle. [4] Transmission control device used in an authentication system (1) which enables the control of an authentication target based on authentication established by verification via wireless communication between the authentication target and a portable device (2) worn by a user, comprising: an antenna driver unit (303) configured to output a driver current to a transmission antenna (31) to cause the transmission antenna (31) to transmit a signal with a specified frequency band; a current setting unit (306) configured to set the driver current output by the antenna driver unit (303); a monitoring unit (304) configured to detect a current flowing through the transmission antenna (31); and a correction value determination unit (307) configured to determine a correction value of the driver current output by the antenna driver unit (303) by feedback control based on the current detected by the monitoring unit (304), wherein After the correction value determination unit (307) determines the correction value, the current setting unit (306) corrects the driver current to transmit as the signal a request signal which is used for verification based on the correction value, and wherein: the authentication target is provided by a vehicle; the transmission control device is mounted on the vehicle; and The correction value determination unit (307) determines the correction value by causing the antenna driver unit (303) to output the driver current to transmit the signal, and the transmission antenna (31) to periodically transmit the signal, when the vehicle is moving. characterized by , that If a radio device is used that is mounted on the vehicle and uses a frequency band that overlaps with the frequency band on which the transmitting antenna (31) transmits the signal, the correction value determination unit (307) does not cause the transmitting antenna (31) to transmit the signal, even when the vehicle is moving; and When the radio is not in use, the correction value determination unit (307) causes the transmission antenna (31) to transmit the signal periodically. [5] Transmission control device used in an authentication system (1) which enables the control of an authentication target based on authentication established by verification via wireless communication between the authentication target and a portable device (2) worn by a user, comprising: an antenna driver unit (303) configured to output a driver current to a transmission antenna (31) to cause the transmission antenna (31) to transmit a signal with a specified frequency band; a current setting unit (306) configured to set the driver current output by the antenna driver unit (303); a monitoring unit (304) configured to detect a current flowing through the transmission antenna (31); and a correction value determination unit (307) configured to determine a correction value of the driver current output by the antenna driver unit (303) by feedback control based on the current detected by the monitoring unit (304), wherein After the correction value determination unit (307) determines the correction value, the current setting unit (306) corrects the driver current to transmit a request signal as the signal, which is used for verification based on the correction value, characterized by , that the correction value determination unit (307) causes the antenna driver unit (303) to output the driver current several times with the same value; and The correction value determination unit (307) determines the correction value by averaging a plurality of correction values ​​of the driver current output by the antenna driver unit (303), which are calculated by the feedback control based on the currents detected by the monitoring unit (304) several times.

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