JP2019161504A - Portable equipment - Google Patents

Abstract

To provide, in portable equipment which executes communication with on-vehicle equipment loaded on a vehicle, a technique to adjust the signal transmission power of a horizontal polarization signal and a vertical polarization signal even when the portable equipment has a limited thickness.SOLUTION: Portable equipment 10 executes communication with on-vehicle equipment 20 loaded on a vehicle 50. A first antenna 160 and a second antenna 162 are connected to a UHF transmitter unit 104. The first antenna 160 has a first polarization characteristic. The second antenna 162 has a second polarization characteristic different from the first polarization characteristic which the first antenna 160 has. The UHF transmitter unit 104 transmits signals to the on-vehicle equipment 20 while alternately switching the first antenna 160 and the second antenna 162.SELECTED DRAWING: Figure 2

Description

  The present invention relates to communication technology, and more particularly to a portable device that performs communication between an on-vehicle device mounted on a vehicle and a portable device possessed by a user.

  Since a horizontally polarized wave is used for a transmitter (portable device) of a keyless entry system for a vehicle and a vertically polarized wave is used for a receiver (on-vehicle device), a null point is generated and a signal from the transmitter is generated. May not be received by the receiver. In order to cope with this, a pattern antenna for radiating a horizontally polarized signal and a loop antenna for radiating a vertically polarized signal are formed in one path on the substrate of the portable device. Transmit signals simultaneously (see, for example, Patent Document 1).

JP 2004-363929 A

  The thickness of the portable device is limited, and if the thickness of the loop antenna cannot be sufficiently secured, the transmission power of the vertically polarized signal is smaller than the transmission power of the horizontally polarized signal. Increasing the transmission power of the vertically polarized signal also increases the transmission power of the horizontally polarized signal.Therefore, it is necessary to limit the transmission power of the horizontally polarized wave in accordance with standards such as the Radio Law. The transmission power of wave signals cannot be increased.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a portable device that performs communication with an in-vehicle device mounted on a vehicle, even when the thickness of the portable device is limited. An object of the present invention is to provide a technique for adjusting the transmission power of a polarized signal and a vertically polarized signal.

  In order to solve the above-described problem, a portable device according to an aspect of the present invention is a portable device that performs communication with an on-vehicle device mounted on a vehicle, and has a first polarization characteristic. And a second antenna having a second polarization characteristic different from the first polarization characteristic of the first antenna, and a transmission for transmitting a signal to the vehicle-mounted device while alternately switching the first antenna and the second antenna. A section.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, in a portable device that performs communication with an in-vehicle device mounted on a vehicle, even when the thickness of the portable device is limited, transmission of a horizontally polarized signal and a vertically polarized signal is performed. You can adjust the power.

FIGS. 1A to 1B are diagrams illustrating an outline of keyless communication by the vehicle wireless communication system according to the first embodiment. It is a figure which shows the structure of the radio | wireless communications system for vehicles of Fig.1 (a). It is a figure which shows the structure of the UHF transmission part of FIG. 2, a 1st antenna, and a 2nd antenna. 4A to 4D are diagrams illustrating an outline of transmission processing by the portable device of FIG. FIGS. 5A to 5D are diagrams illustrating the effects of the portable device of FIG. 6A to 6C are diagrams illustrating an outline of keyless communication by the vehicle wireless communication system according to the second embodiment. It is a figure which shows the structure of the radio | wireless communications system for vehicles of Fig.6 (a). FIG. 10 is a sequence diagram illustrating a processing procedure performed by the vehicle radio communication system according to the third embodiment. It is a sequence diagram which shows another process sequence by the radio | wireless communications system for vehicles which concerns on Example 3. FIG.

Example 1
Before describing the present invention in detail, an outline will be described. In an embodiment of the present invention, a vehicle that performs wireless communication for locking or unlocking a door lock of a vehicle between an on-vehicle device mounted on the vehicle and a portable device (electronic key) possessed by the user. The present invention relates to a wireless communication system. Two types of communication sequences are defined in a vehicle wireless communication system that performs wireless communication between an on-vehicle device and a portable device. The first type is a communication sequence for executing bidirectional communication between the vehicle-mounted device and the portable device, and is called “smart communication”. The second type is a communication sequence for executing one-way communication from the portable device to the vehicle-mounted device, and is called “keyless communication”. Here, keyless communication will be described.

  In keyless communication, when a user attempts to lock or unlock a door lock of a vehicle using a portable device, a signal including a rolling code is transmitted from the portable device. As described above, horizontally polarized waves are used for portable devices, and vertically polarized waves are used for in-vehicle devices. In order to suppress the occurrence of a null point, the portable device is equipped with a pattern antenna and a loop antenna. Since portable devices are required to be small and thin, there is a limit on the thickness. Even under such circumstances, it is required to prevent the transmission power of the horizontally polarized signal from the pattern antenna from becoming too large while ensuring sufficient transmission power for the vertically polarized signal from the loop antenna. Is done. The portable device according to the present embodiment alternately performs signal transmission from the pattern antenna and signal transmission from the loop antenna. Therefore, the transmission power of the signal from the pattern antenna and the transmission power of the signal from the loop antenna are set separately.

  FIGS. 1A and 1B show an outline of keyless communication by the vehicular wireless communication system 1000. FIG. Keyless communication is a communication sequence for unlocking a door lock in wireless communication between an in-vehicle device and a portable device. It is a communication sequence which performs direction communication. The vehicle wireless communication system 1000 includes a portable device 10 and an on-vehicle device 20, and the on-vehicle device 20 is mounted on a vehicle 50. In a situation where the door lock of the vehicle 50 is locked, a user who carries the portable device 10, that is, a user who tries to get into the vehicle 50 performs an operation of unlocking the door lock on the portable device 10. The operation of unlocking the door lock by the user is, for example, that a button (not shown) provided on the portable device 10 is pushed down. The portable device 10 transmits a keyless signal to the vehicle-mounted device 20 when the user performs an operation of unlocking the door lock. The keyless signal is a UHF (Ultra High Frequency) signal, for example, a 300 MHz band signal. The UHF signal is also referred to as an RF (Radio Frequency) signal.

  FIG. 1B shows the format of the keyless signal. For the keyless signal, a preamble, a synchronization signal, and data are arranged in this order. The preamble and the synchronization signal are known signals used for establishing communication between the portable device 10 and the vehicle-mounted device 20. The data includes a function command, an ID code, and a rolling code. The function command indicates information for specifying a function to be executed by keyless communication, for example, unlocking the door lock. The ID code indicates information for identifying the portable device 10. The rolling code indicates a value that increases each time a keyless signal is transmitted from the portable device 10, and is indicated by, for example, 2 bytes. Specifically, the value of the rolling code increases by “1” every time the keyless signal is transmitted. Returning to FIG.

  The vehicle-mounted device 20 receives the keyless signal. The vehicle-mounted device 20 determines whether or not to unlock the door lock of the vehicle 50 based on the ID code and the rolling code included in the keyless signal. In particular, the vehicle-mounted device 20 unlocks the door lock if the rolling code satisfies the conditions. In addition, since a well-known technique should just be used about the conditions with respect to a rolling code, description is abbreviate | omitted here. The communication sequence for locking the door lock is the same.

  FIG. 2 shows a configuration of the vehicular wireless communication system 1000. The vehicle wireless communication system 1000 includes the portable device 10 and the vehicle-mounted device 20 as described above, and the vehicle-mounted device 20 is mounted on the vehicle 50. The portable device 10 includes an operation unit 100, a control unit 102, a UHF transmission unit 104, a first antenna 160, and a second antenna 162. The vehicle-mounted device 20 includes a UHF receiving unit 200 and a control unit 202. The vehicle 50 includes an ECU (Electronic Control Unit) 52 and a door lock mechanism 54.

  The operation unit 100 of the portable device 10 corresponds to the above-described button, and is pressed down when the user requests to lock or unlock the door lock of the vehicle 50. When the operation unit 100 is depressed, the operation unit 100 notifies the control unit 102 of the depression information. The control unit 102 receives a door lock unlocking or locking request based on a notification from the operation unit 100. The control unit 102 generates a keyless signal so as to include a function command, an ID (IDentification) code, and a rolling code. The format of the keyless signal is as described above. The control unit 102 outputs a keyless signal to the UHF transmission unit 104. When the UHF transmission unit 104 receives a keyless signal from the control unit 102, the UHF transmission unit 104 transmits the keyless signal from the first antenna 160 or the second antenna 162 to the vehicle-mounted device 20. Here, switching between the first antenna 160 and the second antenna 162 is controlled by the control unit 102. The structures of the UHF transmission unit 104, the first antenna 160, and the second antenna 162 will be described later.

  The UHF receiver 200 of the in-vehicle device 20 receives a keyless signal from the portable device 10. The UHF receiving unit 200 outputs a keyless signal to the control unit 202. When the keyless signal is input from the UHF receiving unit 200, the control unit 202 extracts a function command, an ID code, and a rolling code included in the keyless signal. The control unit 202 executes pair authentication based on the extracted ID code and the previously stored ID code. Since a known technique may be used for pair authentication, the description thereof is omitted here. If pair authentication fails, the processing described later is not executed. When the pair authentication is successful, the control unit 202 determines whether the condition is satisfied based on the extracted rolling code and the reference rolling code. The condition is defined as “the value of the rolling code is greater than or equal to the value of the rolling code for reference”. The control unit 202 determines locking or unlocking of the door lock according to the function command when the condition is satisfied. On the other hand, when the condition is not satisfied, the control unit 202 refuses to lock or unlock the door lock according to the function command.

  When the control unit 202 determines to lock or unlock the door lock, the control unit 202 instructs the ECU 52 of the vehicle 50 to lock or unlock the door lock mechanism 54. Since a known technique may be used for the ECU 52 and the door lock mechanism 54, description thereof is omitted here. When it is determined to lock or unlock the door lock, or when the door lock mechanism 54 is locked or unlocked, the control unit 202 increments the value of the reference rolling code by “1”, and Holds the value of the rolling code.

  This configuration can be realized by a CPU (Central Processing Unit), memory, or other LSI (Large Scale Integration) of any computer in terms of hardware, and by a program loaded in the memory in terms of software. However, here, functional blocks that are realized by their cooperation are depicted. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms only by hardware, or by a combination of hardware and software.

  FIG. 3 shows the structure of the UHF transmitter 104, the first antenna 160, and the second antenna 162. An RF transmission IC (Integrated Circuit) 152, a switch 154, a first antenna 160, and a second antenna 162 are mounted on a substrate 150 built in the portable device 10. The RF transmission IC 152 includes a crystal resonator, a transistor, and the like, receives a keyless signal from the control unit 102, and outputs a UHF keyless signal to the switch 154.

  The switch 154 receives a signal (hereinafter referred to as “switching signal”) for instructing switching between the first antenna 160 and the second antenna 162 from the control unit 102. When the switching signal indicates the first antenna 160, the switch 154 outputs the keyless signal from the RF transmission IC 152 to the first antenna 160. On the other hand, when the switching signal indicates the second antenna 162, the switch 154 outputs the keyless signal from the RF transmission IC 152 to the second antenna 162. That is, the switch 154 outputs a keyless signal while switching between the first antenna 160 and the second antenna 162.

  The first antenna 160 is formed by patterning a metal layer serving as a conductor on the surface of the substrate 150, and has a substantially rectangular loop pattern. When the UHF keyless signal from the RF transmission IC 152 is transmitted to the first antenna 160, the first antenna 160 transmits the UHF keyless signal to the vehicle-mounted device 20. The first antenna 160 is a pattern antenna and has a polarization characteristic of horizontal polarization. The second antenna 162 is formed to have a portion parallel to the thickness direction of the substrate 150. When the UHF keyless signal from the RF transmission IC 152 is transmitted to the second antenna 162, the second antenna 162 transmits the UHF keyless signal to the vehicle-mounted device 20. Such a second antenna 162 is a loop antenna and has vertical polarization characteristics. When the horizontal polarization is referred to as the first polarization characteristic, the vertical polarization is referred to as the second polarization characteristic.

  Note that the switching signal from the control unit 102 is also input to the RF transmission IC 152. When the switching signal indicates the first antenna 160, the RF transmission IC 152 sets the first amplification factor when the keyless signal is transmitted from the first antenna 160 to the amplifier. When the switching signal indicates the second antenna 162, the RF transmission IC 152 sets the second amplification factor when the keyless signal is transmitted from the second antenna 162 to the amplifier. Here, the first amplification factor and the second amplification factor are different from each other, and a larger value is set for the second amplification factor than the first amplification factor. With this setting, the transmission power for transmitting the keyless signal from the second antenna 162 is made larger than the transmission power for transmitting the keyless signal from the first antenna 160.

  Here, the keyless signal will be described with reference to FIGS. 4A to 4D show an outline of transmission processing by the portable device 10. FIG. 4A shows a keyless signal transmitted from a conventional portable device that includes only the first antenna 160 and does not include the second antenna 162. As illustrated, the third keyless signal is continuously transmitted from the first keyless signal. The same information is included in the first keyless signal to the third keyless signal. The first keyless signal to the third keyless signal are transmitted by horizontal polarization. In FIG. 4B, the sixth keyless signal is continuously transmitted from the first keyless signal. The first keyless signal to the sixth keyless signal contain the same information. The first keyless signal to the third keyless signal are transmitted by horizontal polarization from the first antenna 160 as in FIG. 4A, and the fourth keyless signal to the sixth keyless signal are vertically polarized from the second antenna 162. Sent by.

  In FIG. 4C, the fourth keyless signal is continuously transmitted from the first keyless signal. The first keyless signal to the fourth keyless signal contain the same information. The first keyless signal and the second keyless signal are transmitted from the first antenna 160 by horizontal polarization, and the third keyless signal and the fourth keyless signal are transmitted from the second antenna 162 by vertical polarization. Also in FIG. 4D, the fourth keyless signal is continuously transmitted from the first keyless signal. The first keyless signal is transmitted from the first antenna 160 by horizontal polarization, and the second keyless signal is transmitted from the second antenna 162 by vertical polarization. The third keyless signal is transmitted from the first antenna 160 by horizontal polarization, and the fourth keyless signal is transmitted from the second antenna 162 by vertical polarization. That is, in FIGS. 4B to 4D, the keyless signal is transmitted while the first antenna 160 and the second antenna 162 are alternately switched.

  FIGS. 5A to 5D show the effects of the portable device 10. 5A to 5B show relative angles between the portable device 10 and the vehicle 50. FIG. As illustrated, the direction from the vehicle 50 toward the portable device 10 is defined as “0 °”, and “90 °”, “180 °”, and “270 °” are defined clockwise from there. The direction in which the head of the vehicle 50 faces is indicated by the angle while using the angle defined in this way. 5A shows the relationship between the portable device 10 and the vehicle 50 when the angle is “0 °”, and FIG. 5B shows the relationship between the portable device 10 and the vehicle 50 when the angle is “90 °”. Show the relationship.

  FIGS. 5C to 5D show distances at which the vehicle-mounted device 20 can receive the keyless signal transmitted from the portable device 10. The angle is as shown in FIGS. 5A to 5B, and the distance starts from the center of the vehicle 50. FIG. 5 (c) shows the characteristics of a conventional portable device that includes only the first antenna 160 and does not include the second antenna 162. As described above, the occurrence of a null point shortens the distance in the directions of 90 ° and 270 °. FIG. 5D shows characteristics of the portable device 10 according to the present embodiment. The dependence of the distance on the angle is reduced.

  According to the embodiment of the present invention, since the keyless signal is transmitted while alternately switching the first antenna having the first polarization characteristic and the second antenna having the second polarization characteristic, The transmission power can be adjusted independently. Since the transmission power is adjusted independently for each antenna, even when the thickness of the portable device is limited, it is possible to adjust the transmission power of keyless signals having two types of polarization characteristics. Further, since the first polarization characteristic is horizontal polarization and the second polarization characteristic is vertical polarization, transmission power suitable for horizontal polarization and vertical polarization can be set. Further, since the first antenna is a pattern antenna and the second antenna is a loop antenna, the first antenna can be horizontally polarized and the second antenna can be vertically polarized. In addition, since the first amplification factor set for the first antenna and the second amplification factor set for the second antenna are set to different values, a keyless signal can be transmitted with transmission power suitable for each.

  In addition, since a larger value is set for the second amplification factor than the first amplification factor, the transmission power when transmitting the keyless signal with the vertical polarization is larger than when transmitting the keyless signal with the horizontal polarization. it can. In addition, since the second amplification factor when transmitting a keyless signal with vertical polarization is increased, transmission power when transmitting a keyless signal with vertical polarization can be increased even when the thickness of the portable device is limited. . In addition, since the first amplification factor when transmitting a keyless signal with horizontal polarization is not increased, the keyless signal can be transmitted within the range of the Radio Law. In addition, since the transmission of the keyless signal from the first antenna and the transmission of the keyless signal from the second antenna are alternately switched, the transmission opportunities of the keyless signal can be made equal.

(Example 2)
Next, Example 2 will be described. In the second embodiment, similarly to the first embodiment, wireless for locking or unlocking the door lock of the vehicle between the vehicle-mounted device mounted on the vehicle and the portable device (electronic key) possessed by the user. The present invention relates to a vehicle radio communication system that performs communication. In the first embodiment, keyless communication is described as an object of description, but in the second embodiment, smart communication is described as an object of description. Here, it demonstrates centering on the difference with Example 1. FIG.

  6A to 6C show an outline of smart communication by the vehicle wireless communication system 1000. FIG. Smart communication is also referred to as a smart entry method, a smart key method, or a passive keyless entry (PKE) method. FIG. 6A shows an unlocking operation by the vehicular wireless communication system 1000. The vehicle wireless communication system 1000 includes a portable device 10 and an on-vehicle device 20, and the on-vehicle device 20 is mounted on a vehicle 50. In a situation where the door lock of the vehicle 50 is locked, a user carrying the portable device 10, that is, a user who tries to get into the vehicle 50 touches the door knob of the vehicle 50. The in-vehicle device 20 transmits a search signal to the portable device 10 when the door knob of the vehicle 50 is touched. The search signal is an LF (Low Frequency) signal, for example, a signal in the 125 kHz band. The communication distance of the LF signal is limited to a range of about 2 m from the vehicle 50.

  FIG. 6B shows the format of the search signal. In the search signal, an authentication command and a burst for RSSI (Received Signal Strength Indicator) are arranged in order. The authentication command includes a key ID for identifying the portable device 10 and a function executed by smart communication, for example, a function command for instructing unlocking of the door lock. The key ID is identification information for identifying the portable device 10 in smart communication. The authentication command is encrypted. The RSSI burst is a signal for causing the portable device 10 to measure the received signal strength. Since the RSSI burst may be used as before, the description thereof is omitted here. Returning to FIG.

  When receiving the search signal, the portable device 10 decodes the content of the authentication command. When the portable device 10 recognizes that the search signal is valid from the vehicle-mounted device 20 based on the key ID included in the authentication command, the portable device 10 transmits a response signal to the vehicle-mounted device 20. The response signal is a UHF signal. FIG. 6C shows the format of the response signal. As the response signal, a preamble, a synchronization signal, and data are arranged in this order. The preamble and the synchronization signal are known signals used for establishing communication between the portable device 10 and the vehicle-mounted device 20. The data includes an order ID and a response code. The order ID is an ID for identifying a combination of the vehicle-mounted device 20 and the portable device 10, and is associated with the key ID. The response code is information for indicating that the signal corresponds to the authentication command. Since known techniques may be used for these, description thereof is omitted here. Returning to FIG.

  The vehicle-mounted device 20 receives the response signal. If it determines with the onboard equipment 20 having received the response with respect to the already transmitted search signal from the portable device 10 based on the order ID and the response code included in the response signal, the door lock of the vehicle 50 is unlocked. Note that the same processing is performed for locking the door lock of the vehicle 50 only by changing the contents of the function command.

  FIG. 7 shows a configuration of the vehicular wireless communication system 1000. The vehicle wireless communication system 1000 includes the portable device 10 and the vehicle-mounted device 20 as described above, and the vehicle-mounted device 20 is mounted on the vehicle 50. The portable device 10 includes an operation unit 100, a control unit 102, a UHF transmission unit 104, an LF reception unit 106, a first antenna 160, and a second antenna 162. The vehicle-mounted device 20 includes a UHF receiving unit 200, a control unit 202, and an LF transmitting unit 204. The vehicle 50 includes an ECU 52 and a door lock mechanism 54.

  A sensor (not shown) mounted on the vehicle 50 detects that the user has touched the door knob of the vehicle 50. When notified of detection from the sensor, the ECU 52 outputs the detection result to the control unit 202. When control unit 202 receives the detection result from ECU 52, control unit 202 determines transmission of the search signal in smart communication. The control unit 202 generates a search signal. At that time, the authentication command includes a key ID for identifying the portable device 10. The control unit 202 outputs the search signal to the LF transmission unit 204. The LF transmission unit 204 transmits a search signal to the portable device 10.

  The LF receiver 106 of the portable device 10 receives the search signal from the vehicle-mounted device 20. The LF receiving unit 106 outputs a search signal to the control unit 102. The control unit 102 extracts the key ID included in the search signal. The control unit 102 performs pair authentication based on the previously held key ID and the extracted key ID. If pair authentication fails, the processing described later is not executed. On the other hand, when the pair authentication is successful, the control unit 102 generates a response signal. The control unit 102 outputs a response signal to the UHF transmission unit 104. When receiving the response signal from the control unit 102, the UHF transmission unit 104 transmits the response signal from the first antenna 160 or the second antenna 162 to the vehicle-mounted device 20. Here, the transmission of the response signal from the first antenna 160 or the second antenna 162 is performed in the same manner as the transmission of the keyless signal from the first antenna 160 or the second antenna 162 in the first embodiment.

  The UHF receiver 200 of the in-vehicle device 20 receives a response signal from the portable device 10. If the UHF receiver 200 does not receive a response signal for a certain period after the LF transmitter 204 transmits the search signal, the controller 202 may retransmit the search signal from the LF transmitter 204. The UHF receiving unit 200 outputs a response signal to the control unit 202. Based on the order ID and response code included in the response signal, the control unit 202 recognizes that a response to the already transmitted search signal has been received from the portable device 10. The control unit 202 determines the locking of the door lock of the vehicle 50. When determining that the door lock is to be locked, the control unit 202 locks the door lock mechanism 54 via the ECU 52. A similar process is executed for unlocking the door lock.

  According to the embodiment of the present invention, the response signal is transmitted while alternately switching the first antenna having the first polarization characteristic and the second antenna having the second polarization characteristic. The transmission power can be adjusted independently. Since the transmission power is adjusted independently for each antenna, the transmission power of response signals with two types of polarization characteristics can be adjusted even when the thickness of the portable device is limited. In addition, since the first amplification factor set for the first antenna and the second amplification factor set for the second antenna are set to different values, the response signal can be transmitted with transmission power suitable for each.

  In this case, since a larger value is set for the second amplification factor than the first amplification factor, the transmission power in the case of transmitting the response signal in the vertical polarization is lower than that in the case of transmitting the response signal in the horizontal polarization. Can be big. In addition, since the second amplification factor when transmitting a response signal with vertical polarization is increased, transmission power when transmitting a response signal with vertical polarization can be increased even when the thickness of the portable device is limited. . Further, since the first amplification factor when transmitting a response signal with horizontally polarized waves is not increased, the response signal can be transmitted within the scope of the Radio Law. Further, since the transmission of the response signal from the first antenna and the transmission of the response signal from the second antenna are switched alternately, the transmission opportunities of the response signal can be made equal.

(Example 3)
Next, Example 3 will be described. As in the second embodiment, the third embodiment relates to a vehicular wireless communication system that performs smart communication between an in-vehicle device mounted on a vehicle and a portable device (electronic key) possessed by a user. In the second embodiment, the response signal is transmitted while alternately switching the first antenna and the second antenna. In the third embodiment, the first antenna and the second antenna are switched according to a request from the vehicle-mounted device. Send a response signal. The vehicular wireless communication system 1000 according to the third embodiment is the same type as that shown in FIGS. 6 (a) to 6 (c) and FIG. Here, it demonstrates centering on the difference from before.

  7 receives a response signal from the control unit 102, the UHF transmission unit 104 transmits the response signal from the first antenna 160 to the vehicle-mounted device 20. The UHF receiver 200 of the in-vehicle device 20 receives a response signal from the portable device 10. The UHF receiving unit 200 outputs a response signal to the control unit 202. At that time, the UHF receiver 200 measures the received power of the response signal and outputs the received power to the controller 202. When the received power is greater than the threshold value, the control unit 202 recognizes that a response to the already transmitted search signal has been received from the portable device 10 based on the order ID and response code included in the response signal. . The control unit 202 determines the locking of the door lock of the vehicle 50.

  On the other hand, when the received power is equal to or lower than the threshold value, or when the UHF receiver 200 does not receive a response signal for a certain period after the LF transmitter 204 transmits a search signal, the controller 202 switches the antenna. A request signal is generated for The control unit 202 outputs a request signal to the LF transmission unit 204. The LF transmission unit 204 transmits a request signal to the portable device 10.

  The LF receiver 106 of the portable device 10 receives a request signal from the vehicle-mounted device 20. The LF receiving unit 106 outputs a request signal to the control unit 102. Upon receiving the request signal, the control unit 102 determines switching from the first antenna 160 to the second antenna 162, outputs a switching instruction to the UHF transmission unit 104, and outputs a response signal to the UHF transmission unit 104. . When the switching instruction and the response signal are input from the control unit 102, the UHF transmission unit 104 transmits the response signal from the second antenna 162 to the vehicle-mounted device 20. If the second antenna 162 has already been used, the second antenna 162 is switched to the first antenna 160 according to the request signal. That is, the UHF transmission unit 104 transmits a response signal from one of the first antenna 160 and the second antenna 162 before receiving the request signal, and after receiving the request signal, the UHF transmission unit 104 receives the request signal from the first antenna 160 and the second antenna 162. A response signal is transmitted from the other side. A similar process is executed for unlocking the door lock.

  The operation of the vehicular wireless communication system 1000 configured as described above will be described. FIG. 8 is a sequence diagram showing a processing procedure by the vehicular wireless communication system 1000. The vehicle-mounted device 20 detects a trigger for transmitting the search signal to the portable device 10 (step S10). When the on-vehicle device 20 detects the trigger, the on-vehicle device 20 transmits a search signal to the portable device 10 (step S12). When the portable device 10 receives the search signal, the portable device 10 transmits a response signal to the vehicle-mounted device 20 with horizontally polarized waves (step S14). The vehicle-mounted device 20 locks or unlocks the door lock mechanism 54 (step S16).

  FIG. 9 is a sequence diagram showing another processing procedure performed by the vehicular wireless communication system 1000. The vehicle-mounted device 20 detects a trigger for transmitting the search signal to the portable device 10 (step S50). When the on-vehicle device 20 detects a trigger, the on-vehicle device 20 transmits a search signal to the portable device 10 (step S52). When the portable device 10 receives the search signal, the portable device 10 transmits a response signal to the in-vehicle device 20 with the horizontally polarized wave (step S54). The on-vehicle device 20 detects that the received power of the response signal is equal to or less than the threshold value (step S56). The on-vehicle device 20 transmits a request signal to the portable device 10 (step S58). When the portable device 10 receives the request signal, the portable device 10 switches from horizontal polarization to vertical polarization, and transmits the response signal to the vehicle-mounted device 20 using vertical polarization (step S60). The vehicle-mounted device 20 locks or unlocks the door lock mechanism 54 (step S62).

  According to the embodiment of the present invention, when the request signal is received, the antennas having different polarization characteristics are switched, so that the response signal can be transmitted efficiently.

  The outline of one embodiment of the present invention is as follows. A portable device according to an aspect of the present invention is a portable device that performs communication with a vehicle-mounted device mounted on a vehicle, and includes a first antenna having a first polarization characteristic and a first antenna that the first antenna has. A second antenna having a second polarization characteristic different from the one polarization characteristic; and a transmission unit that transmits a signal to the vehicle-mounted device while alternately switching the first antenna and the second antenna.

  According to this aspect, since the signal is transmitted while alternately switching the first antenna having the first polarization characteristic and the second antenna having the second polarization characteristic, the thickness of the portable device is limited. Even in this case, the transmission power of signals having two types of polarization characteristics can be adjusted.

  The first polarization characteristic of the first antenna may be horizontal polarization, and the second polarization characteristic of the second antenna may be vertical polarization. In this case, since the first polarization characteristic is horizontal polarization and the second polarization characteristic is vertical polarization, transmission power suitable for horizontal polarization and vertical polarization can be set.

  The first antenna may be a pattern antenna, and the second antenna may be a loop antenna. In this case, since the first antenna is a pattern antenna and the second antenna is a loop antenna, the first antenna can be horizontally polarized and the second antenna can be vertically polarized.

  The transmission unit may set different values for the first amplification factor when a signal is transmitted from the first antenna and the second amplification factor when a signal is transmitted from the second antenna. In this case, since the first amplification factor set for the first antenna and the second amplification factor set for the second antenna are set to different values, a signal can be transmitted with transmission power suitable for each.

  The transmission unit may set a larger value for the second gain than the first gain. In this case, since a larger value is set for the second gain than the first gain, the transmission power when transmitting a signal with vertical polarization can be made larger than when transmitting a signal with horizontal polarization. .

  You may further provide the receiving part which receives the request signal of antenna switching from onboard equipment. The transmitting unit transmits a signal from one of the first antenna and the second antenna before the receiving unit receives the request signal, and after the receiving unit receives the request signal, the signal is transmitted from the other of the first antenna and the second antenna. May be sent. In this case, since the antenna is switched when the request signal is received, the signal can be transmitted efficiently.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to each of those constituent elements or combinations of processing processes, and such modifications are also within the scope of the present invention. .

  In the present embodiment, the UHF transmission unit 104 and the UHF reception unit 200 use UHF signals. However, the present invention is not limited to this. For example, signals other than UHF signals may be used. According to this modification, the degree of freedom of configuration can be improved.

  DESCRIPTION OF SYMBOLS 10 Portable machine, 20 Onboard equipment, 50 Vehicle, 52 ECU, 54 Door lock mechanism, 100 Operation part, 102 Control part, 104 UHF transmission part, 150 Board | substrate, 152 RF transmission IC, 154 Switch, 160 1st antenna, 162 1st 2 antennas, 200 UHF receiving unit, 202 control unit, 1000 wireless communication system for vehicle.

Claims (6)

A portable device that performs communication with an in-vehicle device mounted on a vehicle,
A first antenna having a first polarization characteristic;
A second antenna having a second polarization characteristic different from the first polarization characteristic of the first antenna;
A transmitter for transmitting a signal to the vehicle-mounted device while alternately switching the first antenna and the second antenna;
A portable device comprising: The first polarization characteristic of the first antenna is horizontal polarization,
The portable device according to claim 1, wherein the second polarization characteristic of the second antenna is vertical polarization. The first antenna is a pattern antenna;
The portable device according to claim 1, wherein the second antenna is a loop antenna.   The transmission unit sets different values for a first amplification factor when a signal is transmitted from the first antenna and a second amplification factor when a signal is transmitted from the second antenna. The portable device according to any one of claims 1 to 3.   The portable device according to claim 4, wherein the transmission unit sets a larger value for the second gain than the first gain. A receiver that receives an antenna switching request signal from the vehicle-mounted device;
The transmitter transmits a signal from one of the first antenna and the second antenna before the receiver receives the request signal, and after the receiver receives the request signal, the first antenna and the second antenna The portable device according to claim 1, wherein a signal is transmitted from the other of the second antennas.

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