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    • 专利摘要:
    WIRELESS COMMUNICATION SYSTEM In a wireless communication system, an approach determination section (S16, S36) determines whether a handheld device (20) is within close range (412, 422) of one of a plurality of antennas transmitters (40 - 42, 50 - 54) transmitting a primary signal. When the approach determination section determines that the handheld device is within the nearby area, a transmission control section (30) changes a drive voltage from the other of the transmitting antennas arranged outside the nearby area, such that a communication area ( 411, 421, 511, 521, 531, 541) of the other transmitting antenna is increased to surround the area near one of the transmitting antennas, and the primary signal is relayed from the other transmitting antenna.
    公开号:BR112014010176B1
    申请号:R112014010176-0
    申请日:2012-12-13
    公开日:2021-02-02
    发明作者:Takahide Kitahara；Ryutta Atsumi
    申请人:Denso Corporation E Toyota Jidosha Kabushiki Kaisha；
    IPC主号:
    专利说明:

    CROSS REFERENCE TO RELATED ORDER
    [0001] This application is based on Japanese Patent Application No. 2011-277015, filed on December 19, 2011, the description of which is incorporated herein by reference. TECHNICAL FIELD
    [0002] The present description refers to a wireless communication system that performs wireless communication between a unit in a vehicle and a portable device. TECHNICAL FUNDAMENTALS
    [0003] An electronic switch system for a vehicle that controls a door lock operation and an engine start operation based on a result of wireless communication between a unit in a vehicle and a portable device, such as an electronic switch , was known. Such an electronic switch system is described in patent citations 1-3, for example.
    [0004] In such an electronic switch system, a request signal (primary signal) is transmitted from a transmitting antenna arranged on a vehicle to a communication area provided inside or outside a passenger compartment. When the handheld device is within the communication area, the handheld device transmits a response signal (secondary signal) to the vehicle unit in response to the request signal. When the response signal satisfies a predetermined condition, the vehicle unit performs a predetermined operation, such as a door unlocking operation.
    [0005] As described in patent citation 1, transmitting antennas are arranged in different positions of a vehicle, such as doors, a center console and rear seats. Each of the transmitting antennas provides a communication area such that the communication areas do not overlap. In particular, a communication area provided by an indoor transmitting antenna and a communication area provided by an outdoor transmitting antenna are adjusted so as not to overlap.
    [0006] With respect to the systems described in patent citations 2 and 3, a portable device has a function of measuring an intensity of an order signal, such as an indication value of received signal strength (RSSI) and an intensity of radio field, transmitted from a vehicle. Additionally, with respect to the system of patent citation 2, the handheld device transmits a response signal including the measured RSSI value to a unit in vehicle, and the unit in vehicle restricts a retransmission attack based on the RSSI value of the signal Give me an answer.
    [0007] Figure 12 is a diagram of a receiving circuit 900 employed in such a portable device to receive an order signal. Also, Figure 5A illustrates a change in a demodulated waveform of the request signal to respective portions of the receiving circuit 900 when the handheld device is distant from a transmitting antenna, and Figure 5B illustrates a change in the demodulated waveform of the request signal. in the respective portions of the receiving circuit 900 when the handheld is close to the transmitting antenna.
    [0008] Receiver circuit 900 includes a receiving part 910, a demodulating part 920 and a waveform forming part 930. The receiving part 910 includes an antenna coil 911 and capacitor 912 to form a resonance circuit. The demodulating portion 920 performs an envelope demodulation of a received waveform at the receiving portion '910. The waveform forming portion 930 forms the demodulated envelope waveform in a binary signal. The waveform forming part 930 includes a threshold fixing circuit 931. The waveform forming part 930 produces a signal indicating a high or low level, that is, the binary signal, comparing a value of the demodulated envelope wave to a threshold. Also, the threshold fixing circuit 931 serves as a low-pass filter that moderates the demodulated envelope waveform. The threshold is provided by a low-pass filter output.
    [0009] In Figures 5A and 5B, (1) illustrates a baseband waveform of the request signal, and (2) illustrates a waveform at an output point 913 of the receiving part 910. Also, (3) illustrates a waveform at an exit point 921 of the demodulator part 920, and (4) illustrates a waveform (demodulation waveform) at an exit point 933 of the waveform forming part 930. Additionally, the dashed lines 941, 942 of (3) of Figures 5A and 5B illustrate a change in the threshold set in the threshold fixing circuit 931, that is, a value at an output point 932.
    [00010] As shown in (2) of Figures 5A and 5B, rise and fall of the waveform received by the receiving part 910 is slowed relative to the baseband waveform of the order signal shown in (1) of Figures 5A and 5B due to an antenna Q value effect of the antenna coil 911. An intensity of the electric field generated from the transmitting antenna changes in inverse proportion to the cube of a distance. Therefore, when the handheld device is close to the transmitting antenna, the handheld device necessarily receives a strong radio wave, as shown in (2) of Figure 5B.
    [00011] In this case, the threshold cannot follow a change in the demodulated envelope waveform in a section due to an increase in amplitude of the demodulated envelope waveform and an influence of a time constant of the clamping circuit. threshold 931, as shown in (3) of Figure 5B. As a result, the demodulation waveform loses quite a bit, as shown in (4) of Figure 5B.
    [00012] Therefore, in a system where the threshold is fixed based on the slowed waveform due to the Q value of the handheld device antenna and / or the demodulated envelope waveform, when the handheld device is located close to the antenna transmitter, it is difficult to correctly receive the request signal on the handheld device.
    [00013] Patent Citation 1: Japanese Patent No. 3659583 B2
    [00014] Patent Citation 2: Japanese Patent Application Publication No. 2008-240315
    [00015] Patent Citation 3: Japanese Patent No. 4366376 B2 SUMMARY
    [00016] It is an objective of the present description to provide a wireless communication system that enables a portable device to correctly receive a primary signal from a unit in a vehicle, even if the portable device is located near a transmitting antenna.
    [00017] According to one aspect of the present description, a wireless communication system includes a plurality of transmitting antennas, a portable device, a transmission control section and an approach determination section. The transmitting antennas are arranged in different positions than a vehicle. Each of the transmitting antennas transmits a primary signal to a communication area according to their activation voltage. The handheld device receives the primary signal when the handheld device is within the communication area. The transmission control section is integrated into the vehicle and controls the drive voltage of each of the transmitting antennas, to transmit the primary signal from each of the transmitting antennas. The approach determination section is integrated into the vehicle and determines whether the handheld device is within an area close to one of the transmitting antennas transmitting the primary signal. When the approach determination section determines that the handheld device is within the surrounding area, the transmission control section changes the actuation voltage of the other transmitting antenna so that the communication area of the other transmitting antenna is increased to surround the area close to one of the transmitting antennas and the primary signal is relayed from the other transmitting antennas.
    [00018] In the wireless communication device described above, when the handheld device is within the area close to one of the transmitting antennas, the primary signal is relayed from the other transmitting antenna distant from the nearby area to the increased communication area. Therefore, the handheld device receives the primary signal transmitted from the other transmitting antenna located outside the nearby area. Therefore, the handheld device correctly receives the primary signal. BRIEF DESCRIPTION OF THE DRAWINGS
    [00019] The previous and other objectives, characteristics and advantages of the present description will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
    [00020] Figure 1 is a block diagram of a unit in a vehicle of a wireless communication system according to an embodiment of the present description; Figure 2 is a schematic circuit diagram of a vehicle unit transmitting device according to the embodiment; Figure 3 is a schematic diagram illustrating arrangement positions of transmitting devices in a vehicle according to the embodiment; Figure 4 is a circuit diagram of a portable device of the wireless communication system according to the embodiment; Figure 5A is a waveform graph when a handheld device is distant from the transmitting device, where (1) is a baseband waveform for an order signal, (2) is a waveform received at the device portable; (3) it is a demodulated envelope waveform, and (4) it is a demodulation waveform; Figure 5B is a waveform graph when the handheld device is close to the transmitting device, where (1) is a baseband waveform for an order signal, (2) is a waveform received at the device portable; (3) it is a demodulated envelope waveform, and (4) it is a demodulation waveform; Figure 6A is a graph illustrating a change in an RS SI value, as a logical value, with respect to a distance between the handheld device and the transmitting device; Figure 6B is a graph illustrating a change in an RSSI value, as a measurement value, with respect to the distance between the handheld device and the transmitting device; Figure 7 is a flow chart illustrating a process performed by the portable device according to the embodiment; Figure 8 is a flowchart illustrating a process performed by a wireless communication system authentication ECU according to the embodiment; Figure 9 is a flow chart illustrating a process subsequent to the process shown in Figure 8; Figure 10 is a diagram illustrating a change in a communication area of an interior rear transmitting device according to the embodiment; Figure 11 is a flowchart illustrating a process performed by an ECU for authenticating a wireless communication system according to another embodiment; and Figure 12 is a circuit diagram of a receiver circuit of a portable device according to a related technique. DESCRIPTION OF METHODS
    [00021] Hereinafter, embodiments of the present description will be described with reference to the drawings. . .
    [00022] A wireless communication system according to one embodiment is used exemplarily as an intelligent input system (electronic switch system). The intelligent entry system generally performs bidirectional communication between a vehicle unit and a portable device (electronic switch), and performs a door lock and unlock operation and an engine start operation based on a result of bidirectional communication. As shown in Figures 1 and 4, the smart entry system includes a vehicle unit 3 mounted on a vehicle, and a portable device 20.
    [00023] As shown in Figure 1, the unit in vehicle 3 includes an authentication electronic control unit (ECU) 30, transmitting devices, such as indoor transmitting devices 40 and outdoor transmitting devices 50, a tuner 71, a touch sensor 72, a trigger switch 73, a push switch 74, a locking device 75, and an electronic control unit (ECU) for motor 76. The authentication ECU 30 is coupled to the internal transmitting devices 40, the external transmitting devices 50, tuner 71, touch sensor 72, trigger switch 73, push switch 74, locking device 75 and engine ECU 76.
    [00024] As shown in Figure 3, the interior transmitting devices 40 include a front interior transmitting device 41 and a rear interior transmitting device 42. The front interior transmitting device 41 is arranged close to front seats, such as a driver's seat 12 and a front passenger seat 13 in a passenger compartment of a vehicle 1. For example, the front interior transmitting device 41 is arranged on a center console 11 provided between the driver seat 12 and the front passenger seat 13. The device front interior transmitter 41 transmits a request signal to a front interior communication area 411 surrounding a front part of the passenger compartment.
    [00025] The rear interior transmitting device 42 is arranged close to a rear seat 14 in the passenger compartment. For example, the rear interior transmitting device 42 is arranged under the rear seat 14, at a median position of the rear seat 14 with respect to a left and right vehicle direction. The rear interior transmitting device 42 transmits a request signal to a rear interior communication area 421 surrounding a rear part of the passenger compartment.
    [00026] The outer transmitting devices 50 include an outer right front transmitting device 51 arranged in a front right door, an outer left front transmitting device 52 arranged in a front left door, an outer right rear transmitting device 53 arranged in a right rear door , and a rear left outer transmitting device 54 arranged in a rear left door. For example, each of the external transmitting devices 51-54 is arranged on a corresponding door handle. Each of the external transmitting devices 51-54 transmits a request signal to a communication area 511, 521, 531, 541 defined outside the door within a range of approximately 1 m from the corresponding door.
    [00027] Each of the transmitting devices 40, 50 (41, 42, 51 - 54) has the same structure, as shown in Figure 2. In particular, the transmitting device 40, 50 includes an antenna coil 61 and a capacitor of resonance 62. The resonance capacitor oil antenna coil 62 constitutes a resonance circuit 610. The transmitting device 40, 50 additionally includes a drive circuit 63, a regulator 64, an oscillation circuit 65 and a converter 66.
    [00028] The drive circuit 63 excites the resonance circuit 610. The regulator 64 regulates a drive voltage applied to the resonance circuit 610. The oscillation circuit 65 generates an oscillation signal having a predetermined frequency, such as a frequency in an LF band. The predetermined frequency is, for example, 134 kHz. Converter 66 converts the request signal from the authentication ECU 30 into a modulation signal, such as by an amplitude shift switching (ASK) modulation, mixing the request signal and the oscillation signal of the oscillation circuit 65 The drive circuit 63 is a CMOS inverter in which a P 631 channel MOSFET and an N 632 channel MOSFET are coupled in a half-bridge manner.
    [00029] Regulator 64 is configured such that the actuation voltage applied to resonance circuit 610 can be varied according to an instruction from the authentication ECU 30. In normal operation, that is, when the portable device 20 is not located in a close area defined around the transmitting device 40, 50 as a transmitting antenna, the regulator 64 of each transmitting device 40, 50 produces the trigger voltage to form the communication area 411, 421, 511, 521, 531, 541 as shown in Figure 3.
    [00030] In the following, an operation of the transmitting device 40, 50 will be described.
    [00031] When the transmitting device 40, 50 receives the request signal in which a high level signal and a low level signal are combined from the authentication ECU 30, the request signal is converted into the modulation signal by the converter 66. The modulation signal is provided to drive circuit 63.
    [00032] In drive circuit 63, FETs 631, 632 are activated and deactivated according to the modulation signal. When FET 631 is in an active state and FET 632 is in an inactive state, resonance circuit 610 is applied with the drive voltage regulated by regulator 64. When FET 631 is in an inactive state and FET 632 is in an active state, the 610 resonance circuit is grounded. As a result, the resonance circuit 610 performs a resonance operation, an AC current flows in the antenna coil 61. Additionally, a radio wave according to a frequency of the AC current is transmitted from the antenna coil 61, as a radio wave of the order signal.
    [00033] Tuner 71 receives a radio wave from a response signal transmitted from portable device 20. Tuner 71 produces the response signal to the authentication ECU 30 after demodulation. For example, the radio wave of the response signal transmitted from the portable device 20 has a frequency in an RF band, such as a 300 to 400 MHz band. For example, tuner 71 is arranged in a column, such as a column C, located obliquely behind the rear seat 14.
    [00034] The touch sensor 72 is arranged on a rear side of a handle on each door. The touch sensor 72 detects that a user touches the back side of the handle. For example, the touch sensor 72 is provided by an electrostatic capacity sensor. The touch sensor 72 provides a detection signal to the authentication ECU 30.
    [00035] The trigger switch 73 is arranged around the handle to instruct door locking. Trigger switch 73 is, for example, a push switch. When trigger switch 73 is operated, a signal indicating the operation of trigger switch 73 is provided to the authentication ECU 30.
    [00036] Boost switch 74 is arranged on an instrument panel of vehicle 1. Boost switch 74 is provided to instruct to connect an accessory power source and an ignition power source and to instruct the engine start operation . An operation signal from the push switch 74 is provided to the authentication ECU 30.
    [00037] The locking device 75 is provided for each of the doors. The locking device 75 includes a door locking motor (not shown) for locking and unlocking the door. Engine ECU 76 is provided to control an engine (not shown) of vehicle 1.
    [00038] The authentication ECU 30 includes a CPU 31, a memory 32 and the like. The authentication ECU 30 performs several processes relating to the intelligent entry system. For example, when vehicle 1 is in a parked state, the authentication ECU 30 intermittently transmits the request signal via external transmitting devices 50. The request signal includes a command to instruct an operation to the portable device 20, a first security code. subpoena made up of random numbers, and a handheld device ID code 20 as identification information.
    [00039] The smart entry system can include several portable devices 20, and each of the portable devices 20 is named with an ID code. Memory 32 is stored with the ID code of each portable device 20. Authentication ECU 30 extracts any of the ID codes stored in memory 32, and includes the ID code in the order signal.
    [00040] When the authentication ECU 30 receives the response signal from the handheld device 20 through tuner 71, the authentication ECU 30 compares a second subpoena code included in the response signal with its own subpoena code (then, subpoena code) subpoena ECU) obtained by a logical operation of the authentication ECU 30. The second subpoena code is obtained when the handheld device 20 performs a logical operation predetermined by the first subpoena code. The ECU subpoena code is obtained when the authentication ECU 30 performs a logical operation predetermined by the first subpoena code that is transmitted by the authentication ECU 30.
    [00041] When the second subpoena code is authenticated, the authentication ECU 30 activates the touch sensor 72 to fix the touch sensor 72 in a waiting state. When the touch sensor 72 detects that the user touches the handle, the authentication ECU 30 controls the locking device 75 to unlock the door.
    [00042] When trigger switch 73 is operated in a condition where the door is closed, the authentication ECU 30 transmits the request signal inside the passenger compartment via the interior transmitting devices 40 and the request signal outside the passenger compartment by the external transmitting devices 50 to confirm that the user exits vehicle 1 with the portable device 20. When it is confirmed that the user exits vehicle 1 with the portable device 20, that is, when authentication is not accessible inside the passenger compartment , but it is accessible outside the passenger compartment, the authentication ECU 30 controls the locking device 75 to lock the door.
    [00043] When the push switch 74 is operated, the authentication ECU 30 transmits the request signal within the passenger compartment by the interior transmitting devices 40 to confirm that the portable device 20 is within the passenger compartment. When authentication is accessible, the authentication ECU 30 allows to activate the accessory power source and the ignition power source or instructs the engine ECU 76 to start the engine.
    [00044] In this case, before transmitting the request signal, the authentication ECU 30 transmits a wake-up signal by the transmitting devices 40, 50 to start the portable device 20, which is in the standby state (energy saving mode) . When the authentication ECU 30 receives a response signal from the handheld device 20 in response to the wake-up signal, the authentication ECU 30 transmits the request signal in a manner described above. A process performed by the authentication ECU 30 will be described in detail later.
    [00045] Next, the portable device 20 will be described.
    [00046] The portable device 20 is a wireless communication device of the portable type carried by the user of the vehicle 1. As described above, the smart entry system can include the various portable devices 20, such as two portable devices, one corresponding to one master switch and the other corresponding to a backup switch. Figure 4 is a circuit diagram illustrating a structure of each portable device 20.
    [00047] As shown in Figure 4, the portable device 20 includes a microcomputer 21, a receiving circuit 22, an RSSI circuit 27, an RF transmitting circuit 28 and a battery 29. Receiver circuit 22 receives the radio wave from the order signal transmitted from the transmitting device 40, 50, and demodulates the order signal. The receiving circuit 22 has a structure similar to the receiving circuit 900 shown in Figure 12. The receiving circuit 22 includes a receiving part 23, an amplifying part 24, a demodulating part 25 and a waveform forming part 26. The receiving circuit 22 forms a resonance circuit with an antenna coil 231 and a capacitor 232.
    [00048] The amplifying part 24 amplifies the waveform received from the receiving part 23. The demodulating part 25 performs demodulation of the envelope for the waveform amplified by the amplifying part 24. The waveform forming part 26 forms the shape of demodulated envelope wave by demodulator part 25 in a binary signal.
    [00049] When the antenna coil 231 of the receiving part 23 is coupled electromagnetically to the antenna coil 61 of the transmitting device 40, 50, the AC current according to the waveform of the request signal flows in the receiving part 23. In Figures 5A and 5B, (1) illustrates a baseband waveform, that is, a waveform of the request signal, and (2) illustrates a waveform received by the portable device 20, that is, at a point output 233 from the receiving part 23.
    [00050] As shown in (2) of Figures 5A and 5B, an amplitude of the waveform increases according to a high level part of the baseband waveform, and decreases according to a low level part of the form baseband waveform. It is desirable that the waveform of exit point 233 continues to rise and fall from the baseband waveform. In reality, however, the waveform of output point 233 is slowed down due to the influence of the antenna Q value as described above. That is, the amplitude of the waveform received by the portable device 20 does not increase immediately after the baseband waveform returns to the high level, but it gradually increases. Likewise, the amplitude of the waveform received by the portable device 20 does not decrease immediately after the baseband waveform returns to the low level, but it gradually decreases.
    [00051] Demodulator part 25 includes a rectifier diode and the like. In Figures 5A and 5B, (3) illustrates a waveform at an exit point 252 of the demodulator part 25. The waveform forming part 26 includes a threshold fixing circuit 261 and a comparator 263. The fixing circuit threshold 261 is a low-pass filter built of a resistor and a capacitor. The threshold fixing circuit 261 removes a high frequency component from the demodulated envelope waveform by the demodulating part 25, thereby moderating the waveform.
    [00052] In (3) of Figures 5A and 5B, the dashed lines 941, 942 illustrate a change in a threshold fixed in the threshold fixing circuit 261, that is, a value at an output point 262. A demodulation signal out of the demodulating part 25 is introduced to one of the input terminals of the comparator 263, and the threshold set by the threshold fixing circuit 261 is introduced to the other of the input terminals of the comparator 263.
    [00053] Comparator 263 produces a high level signal when the demodulation signal is greater than the threshold value, and produces a low level signal when the demodulation signal is lower than the threshold value. In Figures 5A and 5B, (4) illustrates a waveform at an output point 264 of comparator 263. An output signal from comparator 263 is input to microcomputer 21.
    [00054] The RSSI circuit 27 acquires a signal produced from amplifier part 24, and measures an RSSI value (field strength) of the signal. Figure 6A and Figure 6B are graphs illustrating a change in the RSSI with respect to a distance between the portable device 20 and the transmitting device 40, 50 as the transmitting antenna. In particular, Figure 6A illustrates a theoretical RSSI value, and Figure 6B illustrates a real RSSI value measured by the RSSI circuit 27.
    [00055] As shown in Figure 6A, the RSSI value theoretically increases with a decrease in distance. On the other hand, as shown in Figure 6B, the RSSI value is actually saturated through a measurement range of the RSSI 27 circuit. In Figure 6B, for example, the RSSI value is saturated in a range equal to or more high than 256 dec. The distance between the antenna and the handheld 20 is less than 10 centimeters (cm), in a saturated band. The RSSI value measured by the RSSI circuit 27 is input to the microcomputer 21.
    [00056] The RF transmitting circuit 28 receives a response signal produced from the microcomputer 21, and modulates the response signal to a signal in an RF band. In addition, the RF transmitting circuit 28 transmits the modulated signal.
    [00057] Microcomputer 21 includes a CPU, a memory and the like. Microcomputer 21 performs a process for the intelligent input system. The microcomputer 21 is coupled to the battery 29. The microcomputer 21 is operated using electrical energy from the battery 29. When the microcomputer 21 is not in operation, the microcomputer 21 switches to a standby state, that is, a state of energy saving .
    [00058] Figure 7 is a flow chart of a process performed by microcomputer 21. Hereinafter, the process performed by microcomputer 21 will be described with reference to Figure 7. And to be noted that microcomputer 21 is in the standby state when the process is started.
    [00059] When the process of Figure 7 begins, the microcomputer 21 waits for the wake-up signal from the unit in vehicle 3 (S51). When the microcomputer 21 receives the wake-up signal via the receiving circuit 22 (S51: Yes), the microcomputer 21 switches from the standby state to the normal state and transmits the response signal in response to the wake-up signal (S52).
    [00060] Next, the microcomputer 21 waits for the order signal from the unit in vehicle 3 (S53). When the microcomputer 21 does not receive the request signal before a predetermined period of time elapses, that is, before an interval period, the microcomputer 21 returns to the waiting state. When microcomputer 21 receives a signal before the interval period, microcomputer 21 determines whether the received signal is the request signal including the first subpoena code and the ID code (S54).
    [00061] When the received signal is not the request signal (S54: No), the microcomputer 21 returns to the waiting state. When the received signal is the request signal (S54: Yes), the microcomputer 21 determines whether the ID code of the request signal matches an ED code of the microcomputer 21 (S55).
    [00062] When the ID code of the request signal does not associate with the own ID code of the microcomputer 21 (S55: No), the process resumes to S53. Thus, microcomputer 21 waits for the request signal including the ID code of microcomputer 21. The memory of microcomputer 21 stores its own ID code. Therefore, microcomputer 21 performs S55 determination by extracting the own ID code stored in memory.
    [00063] When the ID code of the request signal is associated with the own ID code of microcomputer 21 (S55: Yes), microcomputer 21 generates the response signal and transmits the response signal through the RF transmitting circuit ( S56). In particular, microcomputer 21 performs a logical operation predetermined to the first subpoena code of the response signal. The logical operation performed by the microcomputer 21 and the logical operation performed by the authentication ECU 30 at authentication are fixed to a common logical operation. Microcomputer 21 produces the response signal including the second subpoena code obtained by the logical operation and the RSSI value of the request signal introduced from the RSSI circuit 27 to the RF transmitting circuit 28 (S56). As such, the response signal including the second subpoena code and the RSSI value is transmitted from RF transmitting circuit 28. After step S56, microcomputer 21 returns to the standby state.
    [00064] In the following, a process performed by the authentication ECU 30 will be described in detail.
    [00065] Figures 8 and 9 are flowcharts illustrating a process performed by the authentication ECU 30. In the process shown in Figures 8 and 9, it is assumed that the request signal is transmitted from the indoor transmitting device 40. For example, the process shown in Figure 8 it starts when the push switch 74 is operated to instruct a motor start.
    [00066] When the process shown in Figure 8 begins, the authentication ECU 30 sets the number of transmission time N of the request signal to "1", that is, it readjusts the number of transmission time N (Sl 1). Next, the authentication ECU 30 transmits the request signal including the command, the first subpoena code and the ID code by the front interior transmitting device 41 (SI2). In this case, the authentication ECU 30 designates any of the ID codes for portable devices 20 stored in memory 32, and includes the ID code designated in the request signal (SI2).
    [00067] Next, the authentication ECU 30 determines whether the transmission time number N is less than a predetermined number (for example, "3" in Figure 8) (SI3). When the transmission time number N is less than the predetermined number (S13: Yes), the authentication ECU 30 determines whether the response signal from the handheld device 20 is received (S14), When the response signal from the handheld device 20 is not received (S14: No), the authentication ECU 30 changes the ID code to be included in the request signal (SI5) and performs the steps from S12 - S14 described above.
    [00068] When the response signal from the handheld device 20 is received (S14: Yes), the authentication ECU 30 determines whether the handheld device 20 is within close range 412 of the front indoor transmitting device 41 based on the RSSI value included in the response signal received (SI6). In this case, the close area 412 is defined around the front interior transmitting device 41 and is smaller than the front communication area 411, in particular, around the antenna coil 61 of the front interior transmitting device 41.
    [00069] The nearby area 412 is defined as an area where the request signal is less likely to be received correctly by the handheld device 20, such as an area where the demodulation waveform is likely to lose somewhat as shown in (4 ) of Figure 5B when the handheld device 20 receives the transmitted order signal from the transmitting device located in the nearby area 412, or an area where the RSSI value measured by the handheld device 20 is likely to be above a measurement range as shown in Figure 6B. For example, the close area 412 is defined in an area approximately 10 cm from the front indoor transmitting device 41,
    [00070] In S16, a threshold of the RSSI value to discriminate inside and outside the nearby area 412 is previously fixed. When the RSSI value included in the response signal is greater than the threshold, the authentication ECU 30 determines that the portable device 20 is within the close area 412 (SI6). When the RSSI value included in the response signal is less than the threshold, the authentication ECU 30 determines that the handheld device 20 is outside the nearby area 412 (S16). For example, when the area close to 412 is defined within 10 cm of the antenna, the threshold of the RSSI value is approximately 200 dec, as shown in Figure 6B.
    [00071] In SI6, when the handheld device 20 is outside the nearby area 412 (S16: No), the authentication ECU 30 determines whether the response signal received is normal, that is, the response signal does not have such an error as the little loss in SI7. When the response signal does not have an error (SI7: Yes), the authentication ECU 30 authenticates whether the second subpoena code included in the response signal corresponds to the ECU subpoena code (SI8).
    [00072] When the second subpoena code of the response signal is authenticated (SI9: Yes), the authentication ECU 30 allows a predetermined operation, such as the engine start (S20), When the second subpoena code of the response signal response is not authenticated (SI9: No), the authentication ECU 30 directly terminates the process in Figure 8,
    [00073] In SI7, when the response signal has an error (SI7: No), the authentication ECU 30 adds “1” to the transmission time number N (S21), and resumes to S12. In this case, the authentication ECU 30 assigns the ID code of the same portable device 20 to the request signal, and transmits the request signal (SI2).
    [00074] In SI6, when the handheld device 20 is within the vicinity area 412 (S16: Yes), the authentication ECU 30 stores the handheld device ID code 20 designated at this transmission time as the ID code to be included at a next order signal (S22). Next, the authentication ECU 30 controls the regulator 64 of the rear interior transmitting device 42 to increase the drive voltage of the antenna coil 61 of the rear interior transmitting device 42 such that the communication area of the rear interior transmitting device 42 is increased by an original communication area 421, as shown by a dashed line in Figure 10, for a communication area 423, as shown by a solid line in Figure 10, surrounding the nearby area 412 (S23). As a result of increasing the drive voltage, the communication area 423 expands out of the passenger compartment.
    [00075] Next, the authentication ECU 30 relays the request signal by the rear interior transmitting device 42 (S24). In this case, the ID code stored in S22 is included in the retransmitted order signal. As such, the request signal transmitted from the rear indoor transmitting device 42 can be received by the portable device 20 located within the nearby area 412 of the front indoor transmitting device 41. In this case, the front indoor transmitting device 41 corresponds to a nearby antenna, and the rear indoor transmitting device 42 corresponds to a distant antenna.
    [00076] Therefore, the portable device 20 can correctly receive the request signal, and the RSSI value can be measured precisely. In addition, even if the communication area 423 expands outside the passenger compartment, it is less likely that another portable device 20 outside the passenger compartment will respond to the request signal.
    [00077] Next, the authentication ECU 30 determines whether the transmission time number N is less than the predetermined number (for example "3" in Figure 8) (S25). When the number of transmission times N is less than the predetermined number (S25: Yes), the process resumes S26.
    [00078] In this case, the authentication ECU 30 receives the response signal from the portable device 20 located within the area nearby 412 of the front indoor transmitting device 41. Therefore, in S26, the authentication ECU 30 determines whether the response signal received it is normal, that is, the response signal received does not have an error.
    [00079] When the response signal has no error (S26: Yes), the authentication ECU 30 performs the steps from SI8 - S20. When the response signal has an error (S26: No), the authentication ECU 30 adds “1” to the transmission time number N (S27), and retransmits the request signal (S24). In S25, when the transmission time number N exceeds the predetermined number (S25: No), the authentication ECU 30 ends the process of Figure 8.
    [00080] In SI3, when the transmission time number N exceeds the predetermined number (S13: No), the authentication ECU 30 considers that there is no portable device 20 in the communication area 411 of the front interior transmitting device 41 and proceeds to the process for the rear interior transmitting device 42 of Figure 9.
    [00081] The process shown in Figure 9 is similar to the process shown in Figure 8. Therefore, a description of similar steps will not be repeated. In the process shown in Figure 9, the transmission time number N is reset (S31), and transmits the request signal from the rear interior transmitting device 42 (S32).
    [00082] When the authentication ECU 30 receives the response signal from the handheld device 20 (S34: Yes), the authentication ECU 30 determines whether the handheld device 20 is within an area close 422 of the rear interior transmitting device 42 (S36 ). When the handheld device 20 is within the nearby area 422 (S36: Yes), the authentication ECU 30 increases the drive voltage of the front indoor transmitting device 41 such that the communication area 411 is increased to surround the nearby area 422 (S43 ), and retransmits the order signal from the front interior transmitting device 41 (S44).
    [00083] As such, the portable device 20 can receive the request signal from the front interior transmitting device 41. In this case, the rear interior transmitting device 42 corresponds to the nearby antenna, and the front interior transmitting device 41 corresponds to the distant antenna.
    [00084] In the present embodiment described above, even if the handheld device 20 is located close to the transmitting antenna, the handheld device 20 can correctly receive the request signal. That is, even if the portable device 20 is located close to one of the transmitting antennas (nearby antenna), since the request signal is transmitted from the other of the transmitting antennas (distant antenna) while increasing the communication area of the other antennas. transmitters, the portable device 20 can correctly receive the request signal transmitted from the other of the transmitting antennas. As such, the smart entry system can work properly. In addition, since the handheld device 20 can accurately measure the RSSI value, the system employing the RSSI value can function correctly. For example, a system that restricts a relay attack, as described in patent citation 2, will be operated correctly.
    [00085] Also, in the case where the request signal including the ID code of the portable device 20 located within the nearby area is relayed from the other of the transmitting antenna (distant antenna), it is less likely that another portable device will respond to the request signal. .
    [00086] The wireless communication system according to the present description is not to be limited to the embodiment described above, but can be modified in several other ways without departing from the scope of the appended claims.
    [00087] For example, the wireless communication system can be configured such that the portable device 20 self-determines whether it is located within the area close to the transmitting antenna based on the RSSI value. In such a case, the portable device 20 performs a process shown in a flowchart of Figure 11, for example. In Figure 11, steps similar to the steps in Figure 7 are designated with the same reference numbers.
    [00088] As shown in Figure 11, when the ID code of the received order signal is associated with its own ID code of the handheld device 20 (S55: Yes), the handheld device 20 determines whether it is within the area close to the transmitting antenna based on the measured RSSI value (S57). When the handheld device 20 determines that it is within the nearby area, the handheld device 20 includes information (close information) notifying that the handheld device 20 is within the close area in the response signal to be transmitted at S56.
    [00089] When the handheld device 20 is not within the area close to the antenna, the handheld device 20 transmits a normal response signal at S56. For example, when the RSSI value is used on the unit in vehicle 3 for another purpose, the handheld device 20 transmits a normal response signal including the RSSI value. When the RSSI value is not used in the unit in vehicle 3 for other purposes, the handheld device 20 transmits a normal response signal without including the RSSI value. In the unit in vehicle 3, that is, in the authentication ECU 30, in S16 of Figure 8 and S36 of Figure 9, it is determined whether the portable device 20 is within the area close to the transmitting antenna based on whether the response signal received includes nearby information. In this case too, an advantageous effect similar to the embodiment described above will be achieved.
    [00090] In the embodiments described above, it is determined whether the portable device 20 is close to the transmitting antenna based on the RSSI value of the request signal. As another example, it can be determined whether the handheld device 20 is close to the transmitting antenna based on the RSSI value of the wake-up signal that is transmitted before the request signal. In such a case, the response signal transmitted at S52 of Figure 7 may include the RSSI value of the wake-up signal.
    [00091] In the embodiments described above, the present description is applied exemplarily to the interior transmitting device. In addition, the present description can be applied to the external transmitting device. For example, when the portable device 20 is within the area close to the indoor transmitting device 40, the communication area of the external transmitting device 50 can be expanded to surround the nearby area. For example, when the portable device 20 is within the area close to the outer transmitting device 50, the communication area of the inner transmitting device 40 or the communication area of another outer transmitting device 50 can be expanded to surround the nearby area.
    [00092] For example, it can be determined whether the handheld device 20 is close to the transmitting antenna by a method using a method other than the RSSI value. For example, a camera can be arranged on vehicle 1 to capture an image of an area close to the transmitting antenna, and it can be determined whether the handheld device 20 is close to the transmitting antenna based on an image photographed by the camera.
    [00093] As another example, the transmitting device 40, 50 may have a function of receiving a radio wave from the portable device 20, and it can be determined whether the portable device 20 is close to the transmitting antenna based on an intensity of the wave of the radio.
    [00094] The present description can be applied to a wireless communication system other than the intelligent entry system. For example, the present description can be applied to a system that transmits signals to a portable device from several transmitting antennas arranged at different positions in a vehicle.
    [00095] In the embodiments described above, the transmitting devices 40, 50 correspond to a transmitting antenna. Authentication ECU 30 corresponds to a transmission control section. The section or element of the authentication ECU 30 executing S16 of Figure 8 and S36 of Figure 9 corresponds to an approximation determination section. The RSSI 27 circuit corresponds to a signal strength measurement section. Tuner 71 corresponds to a receiving section. The section or element of the microcomputer 21 executing S57 of Figure 11 corresponds to a portable device determination section. Memory 32 corresponds to a storage section. The section or element of the authentication ECU 30 performing the S22 step of Figure 8 and the S42 step of Figure 9 corresponds to a section for identifying information designation. The signal transmitted from the transmitting device 40, 50, as well as the wake-up signal and the request signal, corresponds to a primary signal. The response signal transmitted from the portable device 20, like the response signal responding to the wake-up signal, corresponds to a secondary signal. The ID code of the handheld device 20 corresponds to identification information.
    [00096] While only the selected exemplary embodiments have been chosen to illustrate the present description, it will be apparent to those skilled in the art of this description that various changes and modifications can be made to it without departing from the length of the description as defined in the appended claims. In addition, the foregoing description of the exemplary embodiments in accordance with the present description is provided for illustration only, and not for the purpose of limiting the description as defined by the appended claims and their equivalents.
    权利要求:
    Claims (5)
    [0001]
    1. Wireless communication system, comprising: a plurality of transmitting antennas (40 - 42, 50 - 54) being arranged in different positions of a vehicle (1), each of the transmitting antennas (40 - 42, 50 - 54) transmitting a primary signal to a communication area (411, 421, 511, 521, 531, 541) according to an activation voltage thereof; a portable device (20) receiving the primary signal when the portable device (20) is within any of the communication areas (411, 421, 511, 521, 531, 541); a transmission control section (30) being integrated into the vehicle (1) and controlling the drive voltage of each of the transmitting antennas (40 - 42, 50 - 54); and an approach determination section (S16, S36) being integrated into the vehicle (1) and determining whether the handheld device (20) is within close range (412, 422) of one of the transmitting antennas (40 - 42, 50 - 54) transmitting the primary signal, characterized by the fact that: when the approach determination section (S16, S36) determines that the handheld device (20) is within the nearby area (412, 422), the transmission control section (30) changes the actuation voltage of the other transmitting antennae located outside the area close (412, 422) to one of the transmitting antennas (40 - 42, 50 - 54) such that the communication area (411, 421, 511, 521, 531, 541) of the other transmitting antenna (40 - 42, 50 - 54) is increased to surround the area near one of the transmitting antennas (40 - 42, 50 - 54) and the primary signal is retransmitted from the other transmitting antennas (40 - 42, 50 - 54).
    [0002]
    2. Wireless communication system according to claim 1, characterized by the fact that: the portable device (20) includes a signal strength measurement section (27) that measures a primary signal strength than the portable device (20 ) receives, and when the handheld device (20) receives the primary signal, the handheld device (20) transmits a second signal to the vehicle (1), the second signal indicating the primary signal strength measured by the signal strength measurement section (27), the wireless communication system additionally including a receiving section (71) being integrated into the vehicle (1) and receiving the secondary signal, in which: the approach determination section (S16, S36) determines whether the handheld device (20) is within the immediate area (412, 422) based on the primary signal strength indicated by the secondary signal.
    [0003]
    3. Wireless communication system according to claim 1, characterized by the fact that: the portable device (20) includes a signal strength measurement section (27) that measures a primary signal strength than the portable device (20 ) receives, and a handheld device determination section (21) that determines whether the handheld device (20) is within the immediate area (412, 422) based on the primary signal strength measured by the signal strength measurement section ( 27), when the signal strength measurement section (27) determines that the handheld device (20) is within the surrounding area (412, 422), the handheld device (20) transmits a secondary signal to the vehicle (1), the secondary signal including approach information indicating that the handheld device (20) is within the immediate area (412, 422), the wireless communication system additionally including a receiver section (71) being integrated into the vehicle (1) and receiving the secun signal where: the approach determination section (S16, S36) determines that the handheld device (20) is within the nearby area (412, 422) when the receiving section (71) receives the secondary signal including the approach information .
    [0004]
    Wireless communication system according to either of claims 2 or 3, characterized in that: the portable device (20) is one of a plurality of portable devices (20), and each of the plurality of portable devices (20) is provided with identification information to identify each portable device (20), the wireless communication system additionally including: a storage section (32) being integrated into the vehicle (1) and storing the identification information of each one of the portable devices (20); and an identification information designation section (S22, S42) being integrated with the vehicle (1) and designating any of the identification information stored in the storage section (32), where: the transmission control section (30) transmits the primary signal including the identification information designated by the identification information designation section (S22, S42), the portable device (20) transmits the secondary signal only when the identification information included in the primary signal is associated with the information of identification provided to the portable device (20), and when the transmission control section retransmits the primary signal from the other of the transmitting antennas (40 - 42, 50 - 54), the identification information designation section (S22, S42) designates the identification information of the portable device (20) located within the surrounding area (412, 422).
    [0005]
    Wireless communication system according to any one of claims 1 to 4, characterized in that the nearby area (412, 422) is a predetermined area defined around one of the transmitting antennas (40 - 42, 50 - 54) and being smaller than the communication area (411, 421, 511, 521, 531, 541) of one of the transmitting antennas (40 - 42, 50 - 54).
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    法律状态:
    2018-12-04| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2020-06-09| B06U| Preliminary requirement: requests with searches performed by other patent offices: suspension of the patent application procedure|
    2020-12-01| B09A| Decision: intention to grant|
    2021-02-02| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 13/12/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    2021-03-16| B16C| Correction of notification of the grant|Free format text: REF. RPI 2613 DE 02/02/2021 QUANTO AO INVENTOR. |
    优先权:
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    JP2011277015A|JP5795732B2|2011-12-19|2011-12-19|Wireless communication system|
    JP2011-277015|2011-12-19|
    PCT/JP2012/082983|WO2013094661A1|2011-12-19|2012-12-13|Wireless communication system|
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