JP2009019399A - Reception control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reception control device which can prevent degradation of the communication performance thereof caused by external noise. <P>SOLUTION: In the reception control device, an on-vehicle electronic controller determines whether or not receiving processing of a decoding signal output from a receiving circuit is carried out, based on a determination result whether or not a received signal intensity output from the receiving circuit has reached a predetermined value. If it is determined that the receiving processing is carried out, the receiving processing of the decoding signal is carried out, and locking/unlocking of a door lock is carried out. On the premise of this structure, the electronic controller continues the receiving processing irrespective of the determination result of the received signal intensity output from the receiving circuit after starting of the receiving processing of the decoding signal. Therefore even if detection is made that the received signal intensity falls below the predetermined value due to an influence of external noise, the receiving processing is not terminated, which leads to prevention of degradation of the communication performance of the reception control device by the external noise. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reception control apparatus.

Conventionally, as shown in Patent Document 1, for example, a reception control apparatus is known that starts receiving a demodulated signal when the reception intensity of a radio signal exceeds a predetermined value. For example, as disclosed in Patent Document 2, there is also a reception control device that stops reception of a demodulated signal when the reception strength of a radio signal becomes a predetermined value or less from the viewpoint of saving power consumption. Such a reception control device is also assumed to be applied to a vehicle electronic key system as disclosed in Patent Document 3, for example. In this case, the reception control device controls the locking and unlocking of the door through wireless communication with the portable device possessed by the user. That is, when the reception intensity exceeds a predetermined value, the radio signal reception process is started, and when the decrease of the reception signal intensity is detected thereafter, the reception process is stopped.
JP 2004-289459 A Japanese Patent Laid-Open No. 10-32504 JP 2004-343294 A

  However, the conventional reception control apparatus has the following problems. That is, in recent years, wireless networks are expanding rapidly, and along with this, so-called external noise (environmental noise) tends to increase. Then, the influence of external noise on the communication characteristics of the reception control device described above cannot be ignored. Under such circumstances, the reception control apparatus may determine that the detected signal strength is not received due to the influence of external noise during the reception process of the wireless signal. Then, the reception control device stops the reception processing of the wireless signal even though the normal wireless signal transmitted from the portable device is received. As described above, there is a fear that the communication performance (reception performance) of the reception control apparatus is deteriorated due to external noise. In particular, when the reception control device as described above is applied to a vehicle equipped with an electronic key system, there is a concern about a decrease in responsiveness to door locking / unlocking based on wireless communication with a portable device.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a reception control device capable of suppressing a decrease in communication performance due to external noise.

  According to the first aspect of the present invention, whether or not to perform the reception processing of the demodulated signal output from the receiving circuit based on the determination result of whether or not the received signal strength has reached a predetermined value output from the receiving circuit. In the reception control device that performs the reception processing of the demodulated signal and controls a predetermined control target based on the received demodulated signal, after starting the reception processing of the demodulated signal In this case, the gist of the present invention is to continue the reception process regardless of the determination result of the received signal strength.

  According to the present invention, once the demodulated signal reception process is started, the demodulated signal reception process is continuously performed regardless of the received signal strength of the signal received thereafter. During this reception process, even if a determination result indicating that the received signal strength is below a predetermined value is input due to the influence of external noise, the reception process of the demodulated signal is not stopped. Therefore, a decrease in communication performance due to external noise is suppressed.

  According to a second aspect of the present invention, in the reception control device according to the first aspect, the demodulated signal includes unique identification information, and whether the identification information is normal during reception processing of the demodulated signal. If it is determined that it is normal, the reception process is continued regardless of the determination result of the received signal strength. If it is determined that it is not normal, the reception process is stopped. This is the gist.

  According to the present invention, when it is determined that the identification information included in the demodulated signal being received is normal, it is assumed that there is no influence of external noise, and the demodulated signal receiving process is continued regardless of the received signal strength. Done. On the other hand, when it is determined that the identification information included in the demodulated signal being received is not normal, the receiving process is canceled as being affected by external noise. For this reason, for example, an abnormal radio signal affected by external noise is not continuously received, and useless reception processing is suppressed. As a result, power consumption is saved.

  According to a third aspect of the present invention, in the reception control device according to the first or second aspect, the reception circuit is a radio signal transmitted from a portable device possessed by a user to remotely control the control target. The gist of this is that it is received.

  According to the present invention, since the deterioration of communication performance due to external noise is suppressed, control of a control target based on a radio signal from a portable device is smoothly performed. That is, responsiveness to control of a control target based on wireless communication with a portable device is ensured.

  According to the present invention, it is possible to suppress a decrease in communication performance due to external noise.

Hereinafter, an embodiment in which the present invention is embodied in an electronic key system for a vehicle will be described with reference to FIGS. 1 to 4A and 4B.
<Outline of electronic key system>
First, an outline of the electronic key system will be described. As shown in FIG. 1, the electronic key system 11 includes an electronic control device 13 mounted on a vehicle 12 and a portable device (electronic key) 14 possessed by a user. The electronic control device 13 is connected to a transmission circuit 15 and a reception circuit 16 for performing mutual wireless communication with a portable device 14 unique to the vehicle 12, and a door as a control target of the electronic control device 13. A lock 17 is connected. The transmission circuit 15 includes a transmission antenna 15a, and the reception circuit 16 includes a reception antenna 16a. The transmission antenna 15a is provided, for example, at the door handle of the vehicle 12, and the reception antenna 16a is provided in the vehicle interior. The receiving circuit 16 will be described in detail later.

  When the user carries the portable device 14 to get into the vehicle 12 and approaches the vehicle 12, the electronic control device 13 performs mutual wireless communication with the portable device 14 through the transmission antenna 15a and the reception antenna 16a. The validity of the portable device 14 is determined through the communication. That is, the electronic control unit 13 generates a response request signal Sreq for outdoor verification that requests a response from the portable device 14, and transmits the signal to the outside of the vehicle through the transmission antenna 15a at a predetermined control period. Thereby, a detection region for outdoor verification (not shown) is formed around the door of the vehicle 12.

  When the user holds the portable device 14 and approaches the locked vehicle 12 and enters the detection region for outdoor verification, the portable device 14 receives the response request signal Sreq and a predetermined identification code. A response signal Srep for outdoor verification including (identification information) is returned. When the returned response signal Srep is received by the electronic control device 13 through the receiving antenna 16a on the vehicle 12 side, the electronic control device 13 checks the validity of the predetermined identification code included in the received response signal Srep. When it is determined that the door lock 17 is appropriate, the door lock 17 is electronically unlocked or unlocked. The validity of the identification code is determined by whether or not the identification code matches the identification code registered in the vehicle (more precisely, the electronic control unit 13).

<Receiving circuit>
Next, the configuration of the receiving circuit 16 will be described in detail with reference to FIG. As shown in FIG. 2, the reception circuit 16 includes a filter circuit 21, an amplification circuit 22, a demodulation circuit 23, and a signal strength measurement circuit 24. A reception antenna 16 a is connected to the input side of the filter circuit 21. In addition, an amplification circuit 22 is connected to the output side of the filter circuit 21, and a demodulation circuit 23 and a signal intensity measurement circuit 24 are connected to the amplification circuit 22. The demodulating circuit 23 and the signal strength measuring circuit 24 are connected to a microcomputer 25 that constitutes the electronic control unit 13. The filter circuit 21, the amplification circuit 22, the demodulation circuit 23, and the signal strength measurement circuit 24 are integrated as a single IC chip.

  The filter circuit 21 removes noise (so-called external noise, which is an unnecessary signal having an adjacent frequency) included in a radio signal received through the receiving antenna 16a, and sends the signal after removing the noise to the amplifier circuit 22. Output.

  The amplifier circuit 22 amplifies the signal from which noise has been removed by the filter circuit 21, that is, the output voltage of the reception antenna 16 a to a level that can be demodulated, and outputs the amplified signal to the demodulation circuit 23 and the signal strength measurement circuit 24.

  The demodulating circuit 23 demodulates the signal received through the receiving antenna 16a (more precisely, the amplified signal amplified by the amplifying circuit 22), and outputs the demodulated signal Sdem to the microcomputer 25.

  The signal strength measuring circuit 24 detects the strength of the signal received through the receiving antenna 16a (more precisely, the amplified signal amplified by the amplifier circuit 22), and the detection signal Spow corresponding to the strength of the signal is detected by the microcomputer. To 25. The signal strength measurement circuit 24 includes an RSSI (Received Signal Strength Indicator) circuit (not shown). The RSSI circuit outputs an RSSI value representing the signal strength (electric field strength) of the received radio signal as the detection signal Spow. That is, when the RSSI circuit compares the preset signal strength determination threshold value with the signal strength (signal level) of the amplified signal from the amplifier circuit 22 and determines that the amplified signal is greater than or equal to the determination threshold value, the RSSI circuit A low level detection signal Spow is output as a value. Further, when the RSSI circuit determines that the amplified signal from the amplifier circuit 22 is less than the determination threshold, the RSSI circuit outputs a high-level detection signal Spow as the RSSI value. The above-described signal strength determination threshold is set to a value equal to or higher than the signal level that can be demodulated by the demodulation circuit 23.

  The microcomputer 25 includes a storage unit 25a including a nonvolatile memory such as an EEPROM and a flash memory, and a volatile memory. The storage unit 25a stores various data such as various control programs such as a locking / unlocking control program and a communication control program, and a vehicle-side identification code corresponding to an identification code unique to the portable device 14.

  The microcomputer 25 determines whether or not to receive the demodulated signal from the demodulation circuit 23 based on the detection signal Spow from the signal strength measurement circuit 24 based on the communication control program stored in the storage unit 25a. That is, when the high-level detection signal Spow is input from the signal strength measurement circuit 24, the microcomputer 25 determines that there is no radio signal (carrier) and does not perform the reception process of the demodulation signal Sdem from the demodulation circuit 23. . When the low-level detection signal Spow is input from the signal strength measurement circuit 24, the microcomputer 25 determines that there is a radio signal (carrier) and performs reception processing of the demodulated signal Sdem from the demodulation circuit 23.

  Moreover, the microcomputer 25 is based on the locking / unlocking program stored in the memory | storage part 25a, the identification code intrinsic | native to the portable device 14 contained in the demodulation signal Sdem from the demodulation circuit 23, and the vehicle stored in the memory | storage part 25a. The identification code on the side is collated, and when the collation coincides, the door lock 17 is permitted to be unlocked or unlocked.

In the present embodiment, the door lock 17 corresponds to a control target of the present invention, and the electronic control device 13 corresponds to a reception control device of the present invention.
<Operation of electronic key system>
Next, the operation of the electronic key system configured as described above will be described.

  As described above, when a user who has the portable device 14 enters the detection area for outdoor verification formed around the door of the vehicle 12, the portable device 14 returns a response signal Srep to the response request signal Sreq. To do. The response signal Srep is subjected to noise removal through the filter circuit 21, amplified by the amplification circuit 22 at a predetermined amplification factor, and sent to the demodulation circuit 23 and the signal strength measurement circuit 24.

  The microcomputer 25 determines whether or not to receive the demodulated signal Sdem from the demodulating circuit 23 based on the detection signal Spow from the signal strength measuring circuit 24. That is, as shown in the time charts of FIGS. 3A and 3B, the microcomputer 25 has a wireless signal having a predetermined signal level when the low-level detection signal Spow is input from the signal strength measurement circuit 24. It is determined that there is a signal (carrier), and the demodulated signal Sdem from the demodulation circuit 23 is received.

  Here, it is assumed that the signal strength of the radio signal becomes unstable due to the influence of external noise during reception of the demodulated signal Sdem. For example, as shown in the time chart of FIG. 3A, the signal level of the detection signal Spow from the signal strength measurement circuit 24 temporarily changes from a low level to a high level. At this time, the microcomputer 25 determines whether or not the identification code included in the demodulated signal Sdem being received is normal. Whether the identification code is normal is determined based on the code system of the identification code, specifically, the code width of the identification code.

  For example, as shown in the time chart of FIG. 4A, when the regular identification code is “0101010”, each code width (code length) of “1” and “0” constituting the identification code is It is set to a predetermined code width Wa. As shown in the time chart of FIG. 4B, the normal identification code composed of a plurality of bits having the normal code width Wa is influenced by external noise, and each code of “0” and “1” is displayed. There is a case where the code is received with an abnormal code width Wb that cannot be originally obtained. In this case, the microcomputer 25 determines that the identification code is not normal. When the microcomputer 25 determines that the identification code is not normal, the microcomputer 25 cancels the reception processing of the demodulated signal Sdem because it is affected by external noise. Thereby, useless reception processing is avoided, and as a result, power consumption related to the useless reception processing is saved.

  On the other hand, when the microcomputer 25 determines that the identification code is valid, the microcomputer 25 continues the reception process as it is regardless of the signal level of the detection signal Spow from the signal strength measurement circuit 24. The microcomputer 25 determines the validity of the demodulated signal Sdem from the demodulating circuit 23, more precisely the vehicle-side identification code included in the signal, and when determining that it is appropriate, the microcomputer 25 unlocks the door lock 17. Or allow unlocking. On the other hand, when the microcomputer 25 determines that the demodulated signal Sdem is not valid, the microcomputer 25 ends the process without permitting the unlocking or unlocking of the door lock 17.

  As described above, once the normal reception process of the response signal Srep from the portable device 14, more precisely, the demodulated signal Sdem is started, the reception process of the demodulated signal Sdem is continued regardless of the received signal strength thereafter. . For this reason, even though the normal response signal Srep transmitted from the portable device 14 is normally received, the reception process is not stopped. Therefore, as shown in the time chart of FIG. 3A, when the signal level of the detection signal Spow from the signal strength measurement circuit 24 temporarily changes from the low level to the high level, the demodulation signal Sdem is immediately received. Unlike the case of canceling the communication, a decrease in communication performance between the portable device 14 and the electronic control device 13 due to external noise is suppressed.

<Effect of Embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) Whether the electronic control unit 13 performs reception processing of the demodulated signal Sdem output from the receiving circuit 16 based on the determination result of whether or not the received signal strength output from the receiving circuit 16 has reached a predetermined value If it is determined that the reception process is to be performed, the demodulation signal Sdem is received, and the locking and unlocking of the door lock 17 is controlled based on the demodulation signal Sdem. On the premise of such an electronic control device 13, the electronic control device 13 does not depend on the result of the reception signal strength output from the reception circuit 16 after starting the reception processing of the demodulated signal Sdem normally. To continue. For this reason, during the process of receiving the demodulated signal Sdem, even when it is detected that the received signal strength has fallen below a predetermined value due to the influence of external noise, the reception process is not stopped. Therefore, a decrease in communication performance (reception performance) due to external noise is suppressed.

  (2) The demodulated signal Sdem includes identification information unique to the portable device 14. Then, the electronic control unit 13 determines whether or not the identification information included in the demodulated signal Sdem is normal during the reception process of the demodulated signal Sdem. When the electronic control unit 13 determines that the identification information included in the demodulated signal Sdem is normal, the electronic control unit 13 continues the reception process of the demodulated signal Sdem regardless of the determination result of the received signal strength output from the receiving circuit 16. If it is determined that it is not normal, the reception processing of the demodulated signal Sdem is canceled because it is affected by external noise. For this reason, useless reception processing is suppressed. As a result, power consumption is saved.

  (3) The receiving circuit 16 receives a radio signal (here, a response signal Srep) transmitted from the portable device 14 held by the user to remotely control the door lock 17 of the vehicle 12. According to the electronic control device 13, since the deterioration of communication performance due to external noise is suppressed, the control of the door lock 17 based on the radio signal from the portable device 14 is also smoothly performed. That is, the responsiveness of the door lock 17 to the radio signal from the portable device 14 is ensured.

<Other embodiments>
In addition, you may implement this Embodiment as follows.
The transmission circuit 15 and the reception circuit 16 that are made into one chip can be incorporated into the electronic control device 13.

  In the present embodiment, the locking / unlocking of the door lock 17 of the vehicle 12 is controlled through mutual wireless communication with the portable device 14, but based on the unlocking signal or the locking signal transmitted from the portable device 14. The door lock 17 may be unlocked or locked. That is, the present invention is applied to an electronic key system that controls the locking and unlocking of the door lock based on the one-way communication from the portable device 14 to the vehicle 12.

  In the present embodiment, the electronic control unit 13 controls the locking and unlocking of the door lock 17 of the vehicle 12 based on wireless communication with the portable device 14. For example, an engine (not shown) that is a drive source of the vehicle 12 The start permission control may be performed, or a security device (not shown) of the vehicle 12 may be set and released. In the present embodiment, the electronic control unit 13 is a component of an electronic key system for a vehicle that controls the locking and unlocking of the door lock 17 of the vehicle 12. It is good also as a component of the electronic key system for buildings which controls or performs the setting and cancellation | release of the crime prevention apparatus of the said building. As described above, the electronic control device 13 can be applied to any system that controls a control target based on a radio signal received through the receiving circuit 16.

  In the present embodiment, the single electronic control device 13 has the communication control function with the portable device 14 and the lock / unlock control function for the door lock 17, but the communication control function with the portable device 14 is provided. The first electronic control device and the second electronic control device having a lock / unlock control function for the door lock 17 may be divided into two. In this case, the first and second electronic control devices are electrically connected to each other.

  In the present embodiment, the electronic control device 13 (more precisely, the microcomputer 25), when the high level detection signal Spow is input during the reception process of the demodulation signal Sdem, outputs the demodulation signal Sdem. The presence / absence of the influence of external noise is determined based on the determination result of whether or not the included identification information is normal. However, the following is also possible. That is, as shown in the time chart of FIG. 3A, when a high-level detection signal Spow is input from the signal strength measurement circuit 24 during the reception process of the demodulated signal Sdem, the high-level signal is detected. When the input of the detection signal Spow continues for a predetermined time, the electronic control unit 13 stops receiving the demodulated signal Sdem because it is affected by external noise. The predetermined time is set to a time shorter than the theoretical reception time of the regular identification information included in the demodulated signal. The electronic control unit 13 is provided with a timer (not shown) for measuring the detection time of the high level detection signal Spow. In this way, it is possible to preferably stop the reception process for external noise that continuously occurs while ignoring external noise that occurs instantaneously.

  In the present embodiment, the microcomputer 25 is included in the demodulated signal Sdem during the reception process when the signal level of the detection signal Spow changes from the low level to the high level during the reception process of the demodulated signal Sdem. Although it is determined whether or not the identification code is normal, the determination may be performed from the start of the reception process of the demodulated signal Sdem.

  In the present embodiment, the electronic control device 13 (more precisely, the microcomputer 25), when receiving the high-level detection signal Spow during the receiving process of the demodulated signal Sdem, When it is determined that the reception process is not normally performed, the reception process is stopped. However, the following process is also possible. That is, after the reception processing of the demodulated signal Sdem is once started, the received signal strength measured by the signal strength measuring circuit 24, in other words, the detection signal Spow input from the signal strength measuring circuit 24 is low level. In any case, the reception processing of the demodulated signal Sdem is continuously performed. That is, in this case, it is not determined whether the reception state is normal based on the above-described identification code. Even if it does in this way, even if it is detected that the received signal strength is lower than the predetermined value, the reception process is not interrupted, so that a decrease in communication performance due to external noise is suppressed.

<Other technical ideas>
Next, the technical idea that can be grasped from the embodiment will be described below.
An electronic key system comprising the reception control device according to any one of claims 1 to 3, wherein a specific lock is locked and unlocked through wireless communication with a portable device possessed by a user. According to this configuration, deterioration in communication performance between the portable device and the reception control device due to external noise is suppressed.

  The reception control device according to claim 2 or 3, wherein the identification information has a predetermined code system corresponding to the control target, and is in the process of receiving the demodulated signal. A reception control device that determines whether or not the identification information is normal based on the code system. According to this, it can be suitably determined whether or not the demodulated signal is normally received based on the code system of the identification information.

1 is a block diagram showing a schematic configuration of an electronic key system according to an embodiment. The block diagram which shows the schematic structure of a receiving circuit and an electronic control apparatus similarly. (A) is a time chart which similarly shows the detection signal from a signal strength measurement circuit, (b) is a time chart which shows the reception state of a demodulation signal. (A) is a wave form diagram which shows the identification code at the time of normal, (b) is a wave form diagram which shows the identification code at the time of abnormality.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Electronic key system, 13 ... Electronic control apparatus (reception control apparatus), 14 ... Portable machine, 16 ... Reception circuit, 17 ... Door lock (control object), Sdem ... Demodulation signal.

Claims (3)

Based on the determination result of whether or not the received signal strength that has been output from the receiving circuit has reached a predetermined value, it is determined whether or not to receive the demodulated signal output from the receiving circuit, and the receiving process is performed. In the reception control device that performs the reception processing of the demodulated signal when controlling the predetermined control object based on the received demodulated signal,
A reception control apparatus that continuously performs the reception process regardless of the reception signal strength determination result after the demodulation signal reception process is started. The reception control device according to claim 1,
The demodulated signal includes unique identification information;
During the reception process of the demodulated signal, it is determined whether or not the identification information is normal. If it is determined that the identification information is normal, the reception process is continued regardless of the determination result of the received signal strength. And a reception control device that cancels the reception process when it is determined that the result is not normal. In the reception control device according to claim 1 or 2,
The reception control device, wherein the reception circuit receives a radio signal transmitted from a portable device possessed by a user to remotely control the control target.

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