JP5629596B2 - Vehicle wireless communication system - Google Patents

Description

  The present invention relates to a wireless communication system for a vehicle that executes various types of vehicle control through wireless communication between a communication device provided in the vehicle and a communication target thereof.

  As a wireless communication system of this type of vehicle, for example, a system described in Patent Document 1 is known. In the system described in Patent Document 1, a communication device is provided on a door handle of a vehicle. A response request signal is transmitted from this communication device to a communication area of tens of centimeters set around the door handle. In this system, the user has a mobile phone that transmits a response signal including an identification code (ID code) based on reception of the response request signal. That is, a response signal is transmitted from the mobile phone when the user brings the mobile phone close to the door handle of the vehicle. The response signal is received by the communication device and transmitted to a vehicle control unit that executes various controls of the vehicle. The vehicle control unit collates the ID code included in the received response signal with the ID code stored in advance in the built-in memory, and unlocks the vehicle door based on the result of the collation. According to such a wireless communication system, the user can unlock the vehicle door only by carrying the mobile phone, so that convenience is improved.

JP 2005-264625 A

  By the way, in such a radio | wireless communications system, the structure of providing a communication apparatus in the position close | similar to the door glass of a vehicle other than the structure of providing a communication apparatus in a door handle can also be employ | adopted. FIG. 6 shows a perspective structure of the communication device arranged in this way.

  As shown in FIG. 6, in this wireless communication system, the communication device 1 is fixedly provided on the upper portion of the frame portion 3 surrounding the door glass 2 of the rear seat. The communication apparatus 1 transmits a response request signal to the communication area A having a radius of several tens of centimeters centered on itself, as shown in FIG. 7 which shows a cross-sectional structure along the line AA in FIG. Accordingly, if the user brings the mobile phone 4 close to the communication device 1 from the outside of the door glass 2, wireless communication is performed between the mobile phone 4 and the communication device 1 to unlock the vehicle door.

  By the way, when the communication apparatus 1 is arranged in this way, the user's perceived communication distance changes as follows according to the open / closed state of the door glass 2. First, as shown in FIG. 7, when the door glass 2 is in a fully closed state, the user can bring the mobile phone 4 close to the door glass 2 only. For this reason, the perceived communication distance is a distance d10 from the surface of the door glass 2 to the outer edge of the communication area A. On the other hand, as shown in FIG. 8, when the door glass 2 is open, the user can bring the mobile phone 4 close to the vicinity of the communication device 1, so that the perceived communication distance is from the surface of the communication device 1 to the communication area. The distance to the outer edge of A is d11.

  Thus, the perceived communication distance changes from the distance d10 to the distance d11 or from the distance d10 to the distance d11 according to the open / close state of the door glass 2. This is one factor that makes the user feel uncomfortable.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle wireless communication system that can dispel the user's uncomfortable feeling.

In order to solve the above-mentioned problems, the invention according to claim 1 performs transmission / reception of a radio signal through short-range wireless communication between a communication device arranged at a position close to a door glass of a vehicle and a communication target. In a wireless communication system for a vehicle that performs vehicle control through transmission and reception of the wireless signal, an open / closed state detecting unit that detects an open / closed state of the door glass, A transmission output adjusting means for setting the transmission output of the communication device stronger when it is detected that the door glass is in a fully closed state than when the door glass is not in a fully closed state. The gist is to provide.

  If the transmission output of a communication apparatus is adjusted according to the opening / closing state of a door glass like the system, the maximum communication distance of a communication apparatus will change according to the opening / closing state of a door glass. Thereby, since the change of the perceived communication distance resulting from the open / closed state of the door glass can be suppressed, the user's uncomfortable feeling can be eliminated.

In order to solve the above-mentioned problem, the invention according to claim 2 is characterized in that a wireless signal is transmitted and received through short-range wireless communication between a communication device arranged at a position close to a door glass of a vehicle and a communication target thereof. In a vehicle wireless communication system that performs vehicle control through transmission and reception of the wireless signal, an opening / closing state detecting means for detecting an opening / closing state of the door glass, and opening / closing of the door glass detected through the opening / closing state detection means than when the door glass-out based on the condition if it is detected which is located to face the communication device, said door glass is not located to face the communication device is detected And a transmission output adjusting means for strongly setting the transmission output of the communication device.

  According to the system, in a situation where the door glass faces the communication device, that is, in a situation where the perceived communication distance can be shortened, this is accurately detected and the transmission output of the communication device becomes strong. Maximum communication distance increases. This makes it possible to more reliably suppress the bodily change in the communication distance, so that the user's uncomfortable feeling can be accurately eliminated.

  According to the wireless communication system for a vehicle according to the present invention, it is possible to dispel the user's uncomfortable feeling.

The block diagram which shows the system configuration | structure about one Embodiment of the radio | wireless communications system of the vehicle concerning this invention. The flowchart which shows the procedure about the process which adjusts the transmission output of the loop antenna by the radio | wireless communications system of the embodiment. (A) is sectional drawing which shows the operation example of the radio | wireless communications system of the embodiment. (B) is a graph which shows the change tendency of the direction which goes outside a vehicle interior from a communication apparatus about the intensity | strength of the magnetic field formed by a communication apparatus. (A) is sectional drawing which shows the operation example of the radio | wireless communications system of the embodiment. (B) is a graph which shows the change tendency of the direction which goes outside a vehicle interior from a communication apparatus about the intensity | strength of the magnetic field formed by a communication apparatus. The flowchart which shows the procedure of the process which adjusts the transmission output of a loop antenna about the other example of the radio | wireless communications system of the vehicle concerning this invention. The perspective view which shows the example about the vehicle carrying the communication apparatus which performs radio | wireless communication with a mobile telephone. Sectional drawing which shows the cross-section along the AA line of FIG. Sectional drawing which shows the cross-section along the AA line of FIG.

  Hereinafter, an embodiment of a radio communication system for a vehicle according to the present invention will be described with reference to FIGS. First, the configuration of the wireless communication system will be described with reference to FIG. The communication apparatus 1 shown in FIG. 1 is also arranged in the same manner as the communication apparatus 1 illustrated in FIG. That is, the communication device 1 shown in FIG. 1 is also fixedly provided on the upper portion of the frame portion 3 surrounding the door glass 2 of the rear seat. The communication device 1 also performs short-distance wireless communication with the mobile phone 4 in the communication area A with a radius of several tens of centimeters centered on itself as the communication area A. In the present embodiment, wireless communication based on the NFC (Near Field Communication) standard using radio waves having a frequency of HF band (13.56 MHz) is employed as short-range wireless communication.

  As shown in FIG. 1, the communication apparatus 1 includes a reader / writer IC 13 that generates a response request signal by modulating a HF band carrier wave with a command code and forms a magnetic field corresponding to the response request signal with a loop antenna 10. Have. The reader / writer IC 13 also performs a process of demodulating an identification code (ID code) from the response signal when a magnetic field corresponding to the response signal is detected via the loop antenna 10. The communication device 1 also includes a matching circuit 12 for matching between the reader / writer IC 13 and the loop antenna 10, and a variable resistor 11 electrically connected to the loop antenna 10 in series. As a result, when the resistance value of the variable resistor 11 changes, the magnitude of the current flowing through the loop antenna 10 changes, so that the strength of the magnetic field formed by the loop antenna 10, that is, the transmission output of the loop antenna 10 changes. Furthermore, the communication device 1 is connected to a communication control unit 20 mounted on the vehicle via a harness 21 and the like. The communication control unit 20 exchanges various information with the reader / writer IC 13 via the harness 21 and controls the transmission output of the loop antenna 10 by operating the resistance value of the variable resistor 11. That is, in the present embodiment, the variable resistor 11 and the communication control unit 20 are transmission output adjusting means for adjusting the transmission output of the communication device 1. The communication control unit 20 includes a nonvolatile memory 20a, and information such as an ID code is stored in the memory 20a.

  On the other hand, the vehicle has various sensors for detecting the vehicle state and various switches operated by the user. Specifically, the window opening / closing sensor 22 that detects the opening / closing state of the door glass 2 illustrated in FIG. 6, the door lock sensor 23 that detects the locking / unlocking state of the vehicle door, and the engine is operated when starting the engine. An ignition switch 24 is provided. And the output of the door lock sensor 23 and the ignition switch 24 is taken in by the vehicle control part 26 provided in the vehicle. The vehicle control unit 26 is a part that controls a control target such as a door lock device 25 that locks and unlocks a vehicle door, for example. In addition, the vehicle control unit 26 exchanges various information with the communication control unit 20 via an in-vehicle LAN 27 constructed by, for example, CAN (Controller Area Network). The output of the window opening / closing sensor 22 is taken into the communication control unit 20. In the present embodiment, the window open / close sensor 22 is an open / closed state detecting means for detecting the open / closed state of the door glass 2.

  On the other hand, the cellular phone 4 includes a communication module 40 that performs short-range wireless communication with the communication device 1 by magnetic field coupling with the loop antenna 10. The communication module 40 includes an IC chip having a control circuit, a memory, and the like, an antenna, and the like. The communication module 40 has a nonvolatile memory, and an ID code unique to the mobile phone 4 is stored in the memory.

Next, the operation of the radio communication system having such a configuration will be described.
First, for example, when the vehicle control unit 26 detects that the vehicle door is locked through the door lock sensor 23 when the ignition switch 24 is in an OFF state, the vehicle control unit 26 determines that the vehicle is parked. At this time, the vehicle control unit 26 transmits a response request signal transmission command to the communication control unit 20 via the in-vehicle LAN 27. Upon receiving the response request signal transmission command, the communication control unit 20 generates a response request code and transmits the generated response request code to the reader / writer IC 13 at a predetermined cycle. Thereby, the magnetic field according to the response request signal is formed by the loop antenna 10 with a predetermined period, and the communication area A is formed.

  Then, it is assumed that the user brings the mobile phone 4 close to the communication device 1 when the magnetic field corresponding to the response request signal is formed by the loop antenna 10. At this time, when the mobile phone 4 enters the communication area A, the magnetic field formed by the loop antenna 10 is applied to the communication module 40. At this time, the communication module 40 starts by obtaining power by electromagnetic induction. When the activated communication module 40 detects a magnetic field corresponding to the response request signal, the communication module 40 demodulates the response request code from the response request signal and executes processing based on the code. Specifically, a response signal is generated by modulating an HF band carrier wave with an ID code stored in its own memory, and a magnetic field corresponding to the response signal is formed. A magnetic field corresponding to the response signal is detected by the loop antenna 10 of the communication device 1. Accordingly, the reader / writer IC 13 demodulates the ID code from the response signal and outputs the demodulated ID code to the communication control unit 20. When the communication control unit 20 receives the ID code from the communication device 1, the communication control unit 20 compares the ID code with the ID code stored in the memory 20a, and determines that the ID codes match each other through the verification. If so, it is determined that authentication of the mobile phone 4 has been established. And when authentication of the mobile telephone 4 is materialized, a door unlocking command is transmitted to the vehicle control part 26 via in-vehicle LAN27. When receiving the door unlocking command, the vehicle control unit 26 drives the door lock device 25 based on the content of the command to unlock the vehicle door.

On the other hand, in the present embodiment, the transmission output of the loop antenna 10 is adjusted based on the open / closed state of the door glass 2 detected through the window open / close sensor 22.
Next, with reference to FIG. 2, the procedure of the process of adjusting the transmission output of the loop antenna 10 executed through the communication control unit 20 will be described. Note that the processing shown in FIG. 2 is repeatedly executed with a predetermined calculation cycle during a period in which response request signals are periodically transmitted from the communication device 1.

  As shown in FIG. 2, in this process, it is first determined whether or not the door glass 2 is fully closed based on the open / closed state of the door glass 2 detected through the window opening / closing sensor 22 (step S1). ). When it is detected that the door glass 2 is not fully closed (step S1: NO), that is, when the door glass 2 is open, the resistance value of the variable resistor 11 is manipulated as the processing of the subsequent step S2. Thus, the transmission output P of the loop antenna 10 is set to the first transmission output P1. The strength of the first transmission output P1 is such that the strength of the magnetic field formed by the loop antenna 10 is maximum at the position of the communication device 1 when the upper limit value of the magnetic field strength that can be received by the communication module 40 is the maximum allowable value Hmax. It is set to indicate an allowable value Hmax. Note that the value of the maximum allowable value Hmax is determined by a standard such as ISO in order to guarantee the operation of the communication module 40.

  On the other hand, when it is detected that the door glass 2 is in the fully closed state (step S1: YES), the resistance value of the variable resistor 11 is operated as the processing of the subsequent step S3, and the transmission output of the loop antenna 10 is performed. P is set to a second transmission output P2 that is stronger than the first transmission output P1. The strength of the second transmission output P2 is set such that the strength of the magnetic field formed by the loop antenna 10 exhibits the maximum allowable value Hmax at the position of the door glass 2.

  Hereinafter, an operation example (action) of the wireless communication system of the present embodiment will be described with reference to FIGS. 3 and 4. Note that the graphs shown in FIG. 3B and FIG. 4B show the communication with the strength of the magnetic field formed by the communication device 1 on the vertical axis and the position in the direction from the communication device 1 toward the outside of the passenger compartment on the horizontal axis. The change tendency of the intensity | strength of the magnetic field formed with the apparatus 1 is shown. 3B and 4B, the threshold value Hmin indicates the lower limit value (minimum operating magnetic field strength) of the magnetic field strength at which the communication module 40 can operate.

  Assume that the door glass 2 has been opened as shown in FIG. In this case, the transmission output of the communication device 1 is set to the first transmission output P1. For this reason, as shown in FIG. 3B, the strength of the magnetic field formed by the communication device 1 shows the maximum allowable value Hmax at the position x0 of the communication device 1 and becomes weaker as the distance from the communication device 1 increases. And since it becomes below threshold value Hmin in the position x2 which only the distance d1 left | separated from the position x1 of the surface of the communication apparatus 1, the distance d1 becomes the maximum communication distance of the communication apparatus 1. FIG. The communication area A is a range indicated by a two-dot chain line in FIG. In this case, since the user can bring the mobile phone 4 close to the vicinity of the communication device 1, the sensible communication distance is the distance d1.

  On the other hand, it is assumed that the door glass 2 is completely closed as shown in FIG. In this case, the transmission output of the communication device 1 is set to the second transmission output P2. For this reason, as shown in FIG. 4B, the strength of the magnetic field formed by the communication device 1 shows a strength H1 stronger than the maximum allowable value Hmax at the position x0 of the communication device 1, so It becomes the threshold value Hmin or less at a far position x4. Therefore, the maximum communication distance of the communication device 1 is a distance from the position x1 to the position x4 on the surface of the communication device 1, that is, a distance d2 longer than the distance d1. Further, the communication area A expands from the range indicated by the two-dot chain line in FIG. 4A to the range indicated by the one-dot chain line. However, in this case, since the user can only bring the mobile phone 4 close to the door glass 2, the perceived communication distance is a distance d3 from the position x3 on the surface of the door glass 2 to the position x4. By the way, the strength of the magnetic field formed by the loop antenna 10 is set to show the maximum allowable value Hmax at the position x3 of the door glass 2 as shown in FIG. The length is substantially the same as the distance d1 shown in FIG. That is, the perceived communication distances are almost the same. Therefore, even if the door glass 2 is in the fully closed state or in the open state, the user's sense of communication distance hardly changes, so that the user's uncomfortable feeling can be eliminated.

  On the other hand, when the door glass 2 is completely closed as shown in FIG. 4A, the strength of the magnetic field formed by the loop antenna 10 is from the position x0 of the communication device 1 to the position x3 of the door glass 2. It becomes stronger than the maximum allowable value Hmax in the interval. For this reason, this section is a non-guaranteed section in which the operation of the mobile phone 4 cannot be guaranteed. However, when the door glass 2 is completely closed, the mobile phone 4 does not enter this section, so the presence of the non-guaranteed section does not become a problem. Therefore, stable wireless communication between the communication device 1 and the mobile phone 4 can be ensured. Further, if the intensity of the magnetic field formed by the loop antenna 10 is set to be the maximum allowable value Hmax at the position x3 of the door glass 2, the sensible communication distance with the position x3 of the door glass 2 as a reference is maximized. Since the length can be set, when the user brings the mobile phone 4 close to the communication device 1, wireless communication is easily performed between them. For this reason, convenience is improved.

Needless to say, when the door glass 2 is open as shown in FIG. 3A, there is no non-guaranteed section, and thus the operation of the mobile phone 4 is guaranteed.
As described above, according to the wireless communication system for vehicles according to the present embodiment, the following effects can be obtained.

  (1) When it is detected that the door glass 2 is in the fully closed state, the transmission output of the communication device 1 is set stronger than when the door glass 2 is detected not in the fully closed state. . Thereby, since the change of the perceivable communication distance resulting from the opened / closed state of the door glass 2 can be suppressed, a user's uncomfortable feeling can be wiped away.

  (2) When it is detected that the door glass 2 is in the fully closed state, the transmission output of the communication device 1 is set so that the strength of the magnetic field formed by the communication device 1 becomes the maximum allowable value Hmax at the position of the door glass. It was decided to set. Thereby, since the stable wireless communication between the communication device 1 and the mobile phone 4 can be secured, the sensible communication distance based on the position of the door glass 2 can be set to the maximum length. Convenience will be improved.

(3) The mobile phone 4 having a high penetration rate is used as a communication target of the communication device 1. This improves convenience.
(4) Wireless communication based on the NFC standard is used as short-range wireless communication between the communication device 1 and the mobile phone 4. Thereby, since the communication function mounted in the mobile phone 4 can be used as it is, the convenience is improved.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
-You may change the position of the communication apparatus 1 suitably. That is, the communication device 1 may be provided in the lower part of the frame 3 or the communication device 1 may be provided in the vicinity of the door glass of the driver's seat. In short, the communication apparatus 1 should just be provided in the vicinity of one of the door glass of a vehicle.

  In the above embodiment, the transmission output of the communication device 1 is changed based on whether or not the door glass 2 is in the fully closed state. Instead, for example, the door glass 2 faces the communication device 1. Therefore, the transmission output of the communication device 1 may be changed based on whether or not it is positioned. Specifically, as shown by the broken line in FIG. 1, the communication apparatus 1 is provided with a reflectance sensor 14 that detects the reflectance on the door glass 2 side. For example, an infrared sensor can be employed as the reflectance sensor 14. And the communication control part 20 performs the process shown in FIG. 5 based on the output of the reflectance sensor 14. FIG. That is, based on the reflectance detected through the reflectance sensor 14, it is determined whether or not the door glass 2 is positioned facing the communication device 1 (step S4), and the door glass 2 faces the communication device 1. If it is not located (step S4: NO), the transmission output P of the loop antenna 10 is set to the first transmission output P1 (step S2). On the other hand, when the door glass 2 is located facing the communication device 1 (step S4: YES), the transmission output P of the loop antenna 10 is set to the second transmission output P2 (step S3). According to such a configuration, in a situation where the door glass 2 faces the communication device 1, that is, in a situation where the perceived communication distance can be shortened, this is accurately detected and the transmission output of the communication device 1 becomes strong. For this reason, the maximum communication distance of the communication device 1 increases. Therefore, since it is possible to more surely suppress the sensational change in the communication distance, it is possible to accurately dispel the user's uncomfortable feeling.

  When the door glass 2 is detected to be in the fully closed state, the transmission output P of the loop antenna 10 may be set so as to satisfy the relationship “P1 <P <P2”. That is, the transmission output of the loop antenna 10 may be set so that the strength of the magnetic field formed by the communication device 1 is smaller than the maximum allowable value Hmax at the position of the door glass 2. Even in such a configuration, when the door glass 2 is in the fully closed state, the maximum communication distance of the communication device 1 is longer than the maximum communication distance d1 when the door glass 2 is open. It is possible to suppress a change in general communication distance.

  In the above-described embodiment, the mobile phone 4 is used as a communication target of the communication device 1, but instead, an appropriate electronic device such as a card with a built-in NFC communication module may be used.

  In the above embodiment, short-range wireless communication between the communication device 1 and the mobile phone 4 is performed based on the NFC standard, but instead, for example, it may be performed based on a general RFID method. Good.

  In the above embodiment, the vehicle wireless communication system according to the present invention is applied to a wireless communication system for unlocking a vehicle door. Instead of this, for example, the present invention can be applied to a wireless communication system that changes the seat position in accordance with the ID code of the mobile phone 4. In addition, when authentication of the mobile phone 4 is established, the present invention can be applied to a wireless communication system that performs a so-called welcome function such as transmitting a user name by voice or turning on a vehicle light. Furthermore, the present invention can also be applied to a wireless communication system that permits the start of an in-vehicle engine on condition that authentication of the mobile phone 4 is established.

<Appendix>
Next, a technical idea that can be grasped from the above embodiment and its modifications will be additionally described.
(B) pre-Symbol near field communication, and the maximum allowable value A wireless communication, the communication target is the maximum possible field strength received utilizing magnetic coupling between the communication target with the communication device In this case, the setting to increase the transmission output of the communication device is performed by setting the strength of the magnetic field formed by the communication device to be the maximum allowable value at the position of the door glass. A vehicle wireless communication system. When the door glass is in a fully closed state, the user can bring the communication target close to the vicinity of the door glass. Therefore, as in the above system, if the strength of the magnetic field formed by the communication device is set to the maximum allowable value at the position of the door glass, stable wireless communication between the communication device and the communication target Can be secured. In addition, since the perceived communication distance based on the position of the door glass can be set to the maximum length, when the user brings the communication target close to the communication device, wireless communication is performed between them. It becomes easy. For this reason, convenience comes to be improved.

(B) before Symbol vehicle radio communication system, wherein the communication target is a mobile phone. As in the system, if a mobile phone having a high penetration rate is used as a communication target, convenience is improved.

(C) a vehicle radio communication system, wherein the pre-Symbol short-range wireless communication is a wireless communication based on the NFC standard. In recent years, mobile phones are equipped with a communication function based on the NFC standard. Therefore, according to the system described above, the communication function installed in the mobile phone can be used as it is, so that convenience is improved.

  A ... communication area, 1 ... communication device, 2 ... door glass, 3 ... frame part, 4 ... mobile phone, 10 ... loop antenna, 11 ... variable resistor, 12 ... matching circuit, 13 ... reader / writer IC, 14 ... reflectance Sensor, 20 ... Communication control unit, 20a ... Memory, 21 ... Harness, 22 ... Window open / close sensor, 23 ... Door lock sensor, 24 ... Ignition switch, 25 ... Door lock device, 26 ... Vehicle control unit, 27 ... In-vehicle LAN, 40: Communication module.

Claims (2)

A wireless communication system for a vehicle that transmits and receives wireless signals through short-range wireless communication between a communication device arranged at a position close to the door glass of the vehicle and its communication target, and executes vehicle control through transmission and reception of the wireless signals In
Open / closed state detecting means for detecting the open / closed state of the door glass;
When it is detected that the door glass is in a fully closed state based on the open / closed state of the door glass detected through the open / closed state detection means, than when it is detected that the door glass is not in a fully closed state. , Transmission output adjusting means for strongly setting the transmission output of the communication device ;
A wireless communication system for a vehicle, comprising: A wireless communication system for a vehicle that transmits and receives wireless signals through short-range wireless communication between a communication device arranged at a position close to the door glass of the vehicle and its communication target, and executes vehicle control through transmission and reception of the wireless signals In
Open / closed state detecting means for detecting the open / closed state of the door glass;
If it is detected that based-out the door glass opening and closing state of the door glass to be detected through the opening and closing state detecting means is positioned to face the communication device, the door glass is the communication device A transmission output adjusting means for setting the transmission output of the communication device to be stronger than when it is detected that they are not positioned facing each other ;
A wireless communication system for a vehicle, comprising:

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