JP2011234260A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system that can reduce wrong start-up of a mobile equipment due to so-called noise.SOLUTION: A WAKE signal is transmitted at a first transmission output power with a large transmission output power from a vehicle side, as a trigger signal for establishing bidirectional communication between a mobile equipment and the vehicle. In a reception standby state of the WAKE signal, the reception sensitivity of the mobile equipment is set to a first reception sensitivity defined as the lowest reception sensitivity among reception sensitivities allowing reception of the WAKE signal. When the mobile equipment receives the WAKE signal, for example, to start up from the reception standby state of the WAKE signal, the reception sensitivity of the mobile equipment is raised up to a second reception sensitivity. Thus, since the mobile equipment waits the WAKE signal at the first reception sensitivity lower than the second reception sensitivity before start-up, the wrong start-up caused by receiving a signal other than the WAKE signal, that is a signal that may cause a noise for the mobile equipment, is automatically suppressed.

Description

  The present invention relates to a communication system capable of bidirectional communication between a portable device possessed by a user and a communication device.

  In recent vehicles, two-way communication related to key verification is performed between a portable device (electronic key) that a user possesses as a vehicle key and a communication device mounted on the vehicle, and the communication area is properly adapted to the vehicle. A device to which a so-called electronic key system that allows various vehicle controls when a portable device is present is known (see, for example, Patent Document 1).

  In this type of electronic key system, a vehicle-side communication device transmits a call signal called a WAKE signal to a predetermined communication area in order to monitor whether a portable device to be communicated exists around the vehicle. When a portable device is present in the communication area, the portable device is activated upon reception of the WAKE signal and sends a response signal called an ACK signal to respond to a call from the vehicle by the WAKE signal. Send.

  When this ACK signal is received by the communication device on the vehicle side, the communication device checks whether or not the portable device existing in the communication area is a regular portable device. A signal requesting to transmit the ID code of the own device, that is, a request signal is transmitted. When the portable device receives the request signal, the portable device transmits a signal including its own ID code, that is, an ID code signal, in response to a request from the vehicle by the request signal.

  When this ID code signal is analyzed by the communication device on the vehicle side and an ID code that matches the reference ID code stored on the vehicle side is included in the ID code signal, the owner of the authorized portable device Various vehicle controls such as door locking / unlocking and engine starting are permitted.

JP 2002-029385 A (paragraph [0002] to paragraph [0007])

  By the way, even when a portable device used in the electronic key system as described above receives a signal that has the same or similar characteristics as the WAKE signal even if it is not a WAKE signal, it activates and sends an ACK signal as when receiving the WAKE signal. Send. For this reason, it is conceivable that the portable device is activated and an ACK signal is transmitted from the portable device in response to reception of a signal emitted from an electrical appliance while the portable device is being stored at home or office. If the operation continues for a long time, the power consumption at the time of starting the portable device including the transmission of the ACK signal cannot be ignored, and the frequency of replacement of the battery built in the portable device increases.

  The present invention has been made paying attention to such problems, and an object of the present invention is to provide a communication system capable of reducing erroneous activation of a portable device due to so-called noise.

  In order to achieve the above object, the invention according to claim 1 is to establish the bidirectional communication in a communication system capable of bidirectional communication between a portable device possessed by a user and a communication device. A signal transmitted from the communication device as a trigger signal is defined as an interrogation signal, and a reception sensitivity capable of receiving the interrogation signal with respect to the portable device is defined as a first reception sensitivity. Sensitivity adjustment means for setting the reception sensitivity of the portable device to a second reception sensitivity that is higher than the first reception sensitivity when the portable device is activated from a standby state for receiving the call signal based on the reception sensitivity. The gist is to provide.

  According to this configuration, the portable device waits for an interrogation signal with the first reception sensitivity that is lower than the second reception sensitivity before the start-up. For this reason, in comparison with the configuration of waiting for a call signal with a relatively high reception sensitivity such as waiting for a call signal with the second reception sensitivity, other signals different from the call signal, that is, signals that cause noise for the portable device The erroneous start-up of the portable device due to the reception of is naturally suppressed. Therefore, erroneous activation of the portable device due to so-called noise can be reduced. In order to ensure that the portable device is activated when the call signal is received even if the portable device is set to a low sensitivity, for example, for the purpose of differentiating from the noise, for example, a call with a large transmission output. It is possible to adopt a configuration in which a signal is transmitted from a communication device, thereby preparing an environment in which a portable device can be easily activated even with low sensitivity.

  According to a second aspect of the present invention, in the communication system according to the first aspect, the portable device includes a reception determination unit that determines whether the call signal is received by the portable device, and the sensitivity adjustment unit. The gist of the invention is to set the reception sensitivity of the portable device to the second reception sensitivity when the reception determination means determines that the call signal is received by the portable device.

  According to this configuration, the reception sensitivity is raised to the second reception sensitivity only when a regular call signal is received. For example, when the mobile device is erroneously activated due to reception of noise, the reception sensitivity is increased. The first reception sensitivity can be maintained without raising the reception sensitivity to 2, and the portable device can be changed from the activated state to the reception standby state. Here, in a configuration different from the present configuration, that is, in a configuration in which the reception sensitivity is raised to the second reception sensitivity without exception even when the portable device is activated not only with a regular call signal but also with reception of noise, As the period set for the second reception sensitivity increases, noise is easily received based on the so-called high reception sensitivity due to the second reception sensitivity. In this regard, in this configuration, since the device for reducing the period during which the reception sensitivity is set to the second reception sensitivity is elaborated, it is difficult to receive noise in comparison with the other configuration, that is, the noise. Even if the mobile device reaches the mobile device, it is difficult to start the mobile device, so that erroneous start-up of the mobile device due to noise can be reduced.

  Also, the reception sensitivity is raised to the second reception sensitivity only when a regular call signal is received, and a response signal for the call signal is transmitted from the portable device only when the regular call signal is received in this way. You can also do that. When such a configuration is adopted, even if the portable device is erroneously activated due to noise reception, the response signal is not transmitted from the portable device, and thus the response signal transmitted due to noise reception is transmitted. Power consumption of the portable device due to operation can be eliminated. Therefore, for example, when the portable device performs a response signal transmission operation using battery power, consumption of battery power can be suppressed, thereby reducing the frequency of battery replacement and charging. Can do.

  According to a third aspect of the present invention, in the communication system according to the first or second aspect, when the call signal is received by the portable device, a response signal to the call signal is transmitted from the portable device, The transmission output of the call signal for the communication device is defined as a first transmission output, and the communication device transmits the call signal with the first transmission output, so that the communication device transmits the response signal. The gist of the present invention is to provide output adjusting means for transmitting a secondary signal corresponding to the response signal with a second transmission output having a transmission output smaller than that of the first transmission output.

  According to this configuration, in order to establish bidirectional communication, the communication device transmits an interrogation signal with a first transmission output having a transmission output larger than that of the second transmission output. In other words, an environment in which the portable device can be easily started even with low sensitivity is provided. When a response signal from the portable device is received by the communication device, a secondary signal is transmitted from the communication device with the second transmission output. In this way, only the interrogation signal, that is, the trigger signal for establishing bidirectional communication is transmitted with a large transmission output, so that the transmission output of the signal after establishment of communication, such as a secondary signal, can be lowered. Become. For this reason, in comparison with the configuration in which the transmission operation is performed with a relatively large transmission output even after the communication is established, such as transmitting the secondary signal with the first transmission output, the communication device side For example, when the communication system is applied to a vehicle, consumption of battery power mounted on the vehicle can be suppressed. In order to ensure that a secondary signal with a small transmission output is received by the portable device, for example, the reception sensitivity of the portable device is set to a relatively high reception sensitivity like the second reception sensitivity, As a result, it is possible to adopt a configuration in which an environment in which a secondary signal having a small transmission output is easily received can be prepared.

  According to a fourth aspect of the present invention, in the communication system according to any one of the first to third aspects, when the interrogation signal is received by the portable device during the bidirectional communication, When a response signal for the call signal is transmitted and the response signal is received by the communication device, a secondary signal for the response signal is transmitted from the communication device, and the portable device transmits the secondary signal for the bidirectional communication. A reception determination unit configured to determine whether or not a signal transmitted from the communication device is received by the own portable device, wherein the sensitivity adjustment unit determines that the call signal is received by the own portable device by the reception determination unit; When the secondary signal is not received by the mobile device by the reception determination means within a period from when the mobile device is To set the signal sensitivity to a lower reception sensitivity than the second receiving sensitivity has as its gist.

  According to this configuration, the reception sensitivity of the portable device is set to the second reception sensitivity once in response to the reception of noise equivalent to a regular call signal, and a regular secondary signal is generated within a predetermined period. If no reception is received, the reception sensitivity of the portable device can be lowered to a reception sensitivity lower than the second reception sensitivity, for example, the first reception sensitivity. In other words, even if the mobile device starts up due to noise, the reception sensitivity of the mobile device is immediately reduced as soon as it is determined that the start is due to noise. It becomes possible to make a transition to the standby state. Therefore, according to the first aspect of the present invention, the erroneous start of the portable device due to noise is naturally suppressed by slowing down the reception sensitivity of the portable device in the waiting state for receiving the call signal. False start-up can be reduced.

  Further, as described in the second aspect of the invention, when it is assumed that the reception sensitivity is raised to the second reception sensitivity when a regular call signal is received, the following can be performed. . That is, the reception sensitivity is maintained at the second reception sensitivity only when a regular secondary signal is received within a predetermined period, and the secondary signal is only received when the regular secondary signal is received in this way. It is also possible to transmit a reply signal to the mobile device. When such a configuration is adopted, even if the portable device is erroneously activated due to noise reception, a reply signal is not transmitted from the portable device, thereby transmitting a reply signal accompanying noise reception. Power consumption of the portable device due to operation can be eliminated. Therefore, for example, when the portable device performs the transmission operation of the reply signal using the battery power, the consumption of the battery power can be suppressed, thereby reducing the frequency of battery replacement and charging. Can do.

  As an example of a vehicle communication system, a WAKE signal is transmitted from the communication device as an interrogation signal during bidirectional communication, and an ACK signal is transmitted from the portable device as a response signal to the WAKE signal. On the other hand, a VEHICLE signal is transmitted from the communication device, and an ACK signal is transmitted from the portable device in response to the VEHICLE signal. A request signal is transmitted from the communication device in response to the ACK signal, and an ID code signal is transmitted from the portable device in response to the request signal. Here, the secondary signal in the present invention includes all signals other than the WAKE signal corresponding to the interrogation signal among the signals transmitted from the communication apparatus, that is, in the case of the above example, the VEHICLE signal and the request signal are second signals. It is included in the next signal. Therefore, according to the invention described in claim 4, an ACK signal is transmitted from the portable device only when a regular VEHICLE signal is received as a secondary signal, and a regular request signal is received as a secondary signal. In this case, the ID code signal can be transmitted from the portable device only in the case where the portable device is used.

Since this invention is comprised as mentioned above, there exist the following effects.
According to the present invention, it is possible to reduce erroneous activation of a portable device due to so-called noise.

The block diagram which shows the structure of the security system in one Embodiment which actualized the communication system which concerns on this invention to the security system for vehicles. Explanatory drawing which shows a smart communication area. Explanatory drawing which shows an example of the output adjustment control by the collation control apparatus of a security device, and the sensitivity adjustment control by the microcomputer of an electronic key.

Hereinafter, an embodiment in which a communication system according to the present invention is embodied in a vehicle security system will be described.
As shown in FIG. 1, the security system 1 includes a vehicle owner, that is, an electronic key 2 possessed by a user as a vehicle key, and a security device 3 provided on the vehicle side, and bidirectional communication is possible between them. is there. The electronic key 2 is generally called a portable device because of its possession.

  The electronic key 2 has a reception function and a transmission function in wireless two-way communication, and includes a reception antenna 21, a reception circuit 22, a microcomputer 23, a transmission circuit 24, and a transmission antenna 25.

  The receiving antenna 21 is a medium for receiving an LF signal such as a WAKE signal or a request signal transmitted from the security device 3. The LF signal is a signal whose frequency range represented by the symbol LF in the Radio Law is 30 KHz to 300 KHz. The reception circuit 22 demodulates the LF signal received by the reception antenna 21 to generate a reception signal, and outputs the reception signal to the microcomputer 23.

  The microcomputer 23 includes a nonvolatile memory 23a, and an ID code (ID code of the electronic key 2) set individually for the electronic key 2 is stored in the memory 23a. When the reception signal related to the WAKE signal is input from the reception circuit 22, the microcomputer 23 generates an ACK original signal and outputs the ACK original signal to the transmission circuit 24 in order to respond to the WAKE signal. The microcomputer 23 generates a signal (ID code original signal) including the ID code of the electronic key 2 in order to respond to the request signal when the reception signal related to the request signal is input from the reception circuit 22. The ID code original signal is output to the transmission circuit 24.

  The transmission circuit 24 modulates the ACK original signal and ID code original signal input from the microcomputer 23 into radio waves of a predetermined frequency (312 MHz in this embodiment), and generates a UHF signal such as an ACK signal and an ID code signal. The UHF signal is a signal having a frequency range of 300 MHz to 3 GHz represented by the symbol UHF in the Radio Law. The transmission antenna 25 is a medium for transmitting the UHF signal generated by the transmission circuit 24.

  The electronic key 2 includes a button type battery (not shown) as a power source. The electronic key 2 covers the power from the button type battery and performs a series of communication operations from reception of the WAKE signal to transmission of the ID code signal. Various operations are performed. In this embodiment, the button-type battery is a primary battery that cannot be charged, and the electronic key 2 is configured so that it can be replaced with a new one when it is consumed.

  The security device 3 has a transmission function and a reception function in wireless two-way communication, and includes a transmission circuit 31, a transmission antenna 32, a reception antenna 33, a reception circuit 34, and a verification control device 35. In the vehicle of this embodiment, various control devices are electrically connected via an in-vehicle communication network. Hereinafter, for convenience of explanation, these control devices are collectively referred to as a collation control device, which is denoted by reference numeral 35. As will be described later, the verification control device 35 mainly performs security control related to electrical key verification necessary to allow various vehicle controls.

  The transmission circuit 31 modulates the WAKE original signal and the request original signal input from the verification control device 35 into radio waves of a predetermined frequency (134 KHz in this embodiment), and generates an LF signal such as a WAKE signal and a request signal. The transmission antenna 32 is a medium for transmitting the LF signal generated by the transmission circuit 31.

  Here, the LF signal from the transmission antenna 32 is transmitted to the smart communication area A32 shown in FIG. In the present embodiment, the smart communication area A32 is defined as an area having a radius of about 1 m around the door outside handle of the driver's seat door outside the vehicle. In this smart communication area A32, bidirectional communication between the electronic key 2 and the security device 3 is possible. That is, when the WAKE signal is transmitted to the smart communication area A32 and the electronic key 2 is brought into the smart communication area A32, the WAKE signal is received by the electronic key 2 and an ACK signal is received from the electronic key 2. Is transmitted, and when the request signal is received by the electronic key 2, the ID code signal is transmitted from the electronic key 2.

  Returning to FIG. 1, the receiving antenna 33 is a medium for receiving a UHF signal such as an ACK signal or an ID code signal transmitted from the electronic key 2. The reception circuit 34 demodulates the UHF signal received by the reception antenna 33 to generate a reception signal, and outputs the reception signal to the verification control device 35.

  The collation control device 35 includes a non-volatile memory 35a, and the memory 35a includes an ID code (reference ID code) that is the same as the ID code of the regular electronic key 2 that is suitable for a vehicle on which the security device 3 is mounted. ) Is stored.

  When the door lock is locked, the verification control device 35 has an electronic key (which is not necessarily the regular electronic key 2) that is a target of bidirectional communication with the security device 3 in the smart communication area. In order to monitor whether or not it exists in A32, the WAKE original signal is output to the transmission circuit 31 periodically (in this embodiment, every 0.3 seconds). That is, in this case, the collation control device 35 performs the first call control. As a result, a WAKE signal is transmitted from the transmission antenna 32 toward the smart communication area A32.

  When the reception signal related to the ACK signal is input from the reception circuit 34 in accordance with the execution of the first call control, the verification control device 35 is an electronic key to be communicated (this is the normal electronic key 2 and Is not present in the smart communication area A32. When the verification control device 35 recognizes in this way, it outputs a request original signal to the transmission circuit 31 in order to check whether or not the electronic key existing in the smart communication area A32 is the regular electronic key 2. To do. That is, in this case, the collation control device 35 performs ID code request control. As a result, a request signal is transmitted from the transmission antenna 32 toward the smart communication area A32.

  The collation control device 35 receives the ID code and the reference ID code included in the received signal when the received signal related to the ID code signal is input from the receiving circuit 34 in accordance with the execution of the ID code request control. It is judged whether or not. That is, in this case, the collation control device 35 performs electrical key collation. And the collation control apparatus 35 recognizes that the regular electronic key 2 exists in smart communication area A32, when both ID codes correspond by the said key collation. Then, when the collation control device 35 detects a touch operation on the door outside handle through a door handle sensor (not shown) in the state of recognition in this way, in this case, the ride by the owner of the authorized electronic key 2 The door lock will be unlocked.

  In addition, the collation control device 35 is configured such that when a door lock switch (not shown) provided outside the vehicle is operated, an electronic key (which is a normal electronic key 2 and a target of two-way communication with the security device 3). However, the WAKE original signal is output to the transmission circuit 31 in order to monitor whether or not it exists in the smart communication area A32. That is, in this case, the collation control device 35 performs the second call control. As a result, a WAKE signal is transmitted from the transmission antenna 32 toward the smart communication area A32.

  When the received signal related to the ACK signal is input from the receiving circuit 34 as a result of performing the second call control, the verification control device 35 is an electronic key to be communicated (this is the normal electronic key 2 and Is not present in the smart communication area A32. When the verification control device 35 recognizes in this way, it outputs a request original signal to the transmission circuit 31 in order to check whether or not the electronic key existing in the smart communication area A32 is the regular electronic key 2. To do. That is, in this case, the collation control device 35 performs ID code request control. As a result, a request signal is transmitted from the transmission antenna 32 toward the smart communication area A32.

  The collation control device 35 receives the ID code and the reference ID code included in the received signal when the received signal related to the ID code signal is input from the receiving circuit 34 in accordance with the execution of the ID code request control. It is judged whether or not. That is, in this case, the collation control device 35 performs electrical key collation. And the collation control apparatus 35 recognizes that the regular electronic key 2 exists in smart communication area A32, when both ID codes correspond by the said key collation. When the verification control device 35 recognizes in this way, in this case, the intention of getting off the vehicle by the owner of the authorized electronic key 2 is recognized, so the door lock is locked. Since the door lock is locked under the condition that the electronic key 2 is taken out of the vehicle in this way, the door lock is locked without leaving the electronic key 2 in the vehicle. The occurrence of lock can be prevented.

  By the way, the microcomputer 23 of the electronic key 2 determines whether or not the normal WAKE signal is received with the own key when the own key is activated from the standby state for waiting for the WAKE signal, for example, when the WAKE signal is received with the own key. WAKE determination is performed to determine whether or not. When the microcomputer 23 makes a positive determination that the normal WAKE signal has been received by its own key based on the WAKE determination, the microcomputer 23 generates an ACK original signal to respond to the WAKE signal. As a result, the ACK signal is generated from the electronic key 2. ACK reply is transmitted. Even when the electronic key 2 is not a regular WAKE signal but has a signal having the same or similar characteristics, that is, a signal that causes noise for the electronic key 2, the electronic key 2 is activated in the same manner as when the WAKE signal is received. WAKE determination by the microcomputer 23 is performed. However, at the time of activation accompanying noise reception, it is not determined that the normal WAKE signal has been received by the own key by the WAKE determination, and therefore no ACK reply is performed.

  The electronic key 2 consumes the electric power stored in the button-type battery not only when the ACK reply is executed, but also when the WAKE determination is performed even if the ACK reply is not reached. As described above, since the battery power is consumed somewhat when the electronic key 2 is activated regardless of the activation trigger, the security system 1 according to the present embodiment is devised to reduce erroneous activation of the electronic key 2 due to noise. It is elaborated. The ease of transition of the WAKE signal from the reception standby state to the activation state is determined by the reception sensitivity in the reception standby state. The higher the reception sensitivity, the more electronic the WAKE signal or noise reaches the electronic key 2. The key 2 is easily activated, and the lower the reception sensitivity, the less likely the electronic key 2 is activated even if the WAKE signal or noise reaches the electronic key 2. In addition, assuming that the reception sensitivity of the electronic key 2 is fixed to a specific reception sensitivity, the WAKE signal or noise transmission output, strictly speaking, the electronic key 2 is slightly attenuated by the radio wave emitted from the transmission source. The electronic key 2 is more likely to be activated as the reception strength at the time of reaching 2 is greater, and the electronic key 2 is less likely to be activated as the reception strength is lower.

  Here, the WAKE signal transmission output for the security device 3 is defined as the first transmission output, and the WAKE signal emitted from the security device 3 is slightly attenuated by the first transmission output, while the outer edge of the smart communication area A32 The reception strength at the time when the electronic key 2 existing in is reached is defined as the first reception strength. Note that the first reception intensity is determined through, for example, experiments performed for each vehicle type and grade using parameters such as a vehicle environment such as temperature and humidity, and a communication environment that takes into account the effects of assumed noise and obstacles. It is calculated, and a specific error range is taken into consideration, and further, it is obtained in consideration of product tolerances due to circuit constants of the transmitting antenna 32 and the receiving antenna 21. Then, for the electronic key 2, the lowest reception sensitivity among the reception sensitivities that can receive the WAKE signal that has reached the self key at the first reception intensity is defined as the first reception sensitivity. In the present embodiment, the WAKE signal In the reception standby state, the reception sensitivity of the electronic key 2 is set to the first reception sensitivity.

  Then, the microcomputer 23 of the electronic key 2 performs a WAKE determination when the own key is activated from the WAKE signal reception standby state, and when an affirmative determination is made in the WAKE determination, the reception sensitivity of the own key is set to the first reception. The second reception sensitivity, which is higher than the sensitivity, is set. When an affirmative determination is made in the WAKE determination as described above, an ACK reply by the electronic key 2 is performed, and when the ACK signal is received by the security apparatus 3 along with this ACK reply, the security apparatus 3 performs verification control. Based on the output adjustment control by the device 35, the request signal is output with the second transmission output whose transmission output is smaller than that of the first transmission output. The reception intensity when the request signal issued from the security device 3 by the second transmission output reaches the electronic key 2 existing at the outer edge of the smart communication area A32 while being slightly attenuated is defined as the second reception intensity. Stipulate. Then, the smallest transmission output among the transmission outputs that can be received by the electronic key 2 when the request signal reaches the electronic key 2 with the second reception intensity is defined as the second transmission output. The second transmission output is calculated through, for example, an experiment performed for each vehicle type or grade, using as a parameter the vehicle environment such as temperature and humidity, and the communication environment considering the influence of assumed noise, obstacles, and the like. In addition to this, a specific error range is taken into consideration, and further, a product tolerance due to circuit constants of the transmission antenna 32 and the reception antenna 21 is determined.

  Incidentally, when the microcomputer 23 of the electronic key 2 makes an affirmative determination in the WAKE determination as described above, it recognizes that the request signal is transmitted later from the security device 3 with the second transmission output having a low transmission output. . Therefore, the microcomputer 23 of the electronic key 2 keeps the reception sensitivity of the own key set to the high-sensitivity second reception sensitivity so that the request signal with a small transmission output is reliably received by the own key. .

  Note that the microcomputer 23 of the electronic key 2 does not raise the reception sensitivity of the own key to the second reception sensitivity when a negative determination is made in the WAKE determination as in the case where the own key is erroneously activated due to reception of noise. While maintaining the first reception sensitivity, the own key is shifted from the activated state to the WAKE signal reception standby state.

  Then, the microcomputer 23 of the electronic key 2 elapses for a certain period of time after an affirmative determination in the WAKE determination, that is, a certain period of time defined as the time until the reception signal related to the request signal should be input from the reception circuit 22. It is determined whether or not a reception signal related to a regular request signal has been input from the reception circuit 22 within a period until the reception. That is, in this case, the microcomputer 23 of the electronic key 2 performs request determination. When the microcomputer 23 of the electronic key 2 makes an affirmative determination in the request determination, it lowers the reception sensitivity of the own key to a reception sensitivity lower than the second reception sensitivity, in this embodiment, the first reception sensitivity. . The reason for this is that since a positive determination is made in the request determination by the electronic key 2 during a series of two-way communication between the electronic key 2 and the security device 3, no signal is sent from the security device 3 thereafter. This is because it is not transmitted, so that the reception operation by the electronic key 2 is not hindered, but rather the possibility that the electronic key 2 receives noise can be reduced.

  When the microcomputer 23 of the electronic key 2 makes a negative determination that the received signal related to the request signal has not been input from the receiving circuit 22 within the period from when the WAKE determination is affirmed until the predetermined time elapses, The reception sensitivity of the key is lowered to a reception sensitivity lower than the second reception sensitivity, in this embodiment, the first reception sensitivity. The reason for this is that the affirmative decision was not made in the request decision within the period after the affirmative decision was made in the WAKE decision, but the received signal subject to the WAKE decision was originally due to noise rather than the received signal related to the regular WAKE signal. This is because there is an aim to immediately reduce the reception sensitivity of the electronic key 2 at the time when the identification is possible. That is, there is a possibility that the electronic key 2 receives noise by lowering the reception sensitivity of the electronic key 2 while avoiding that the reception sensitivity of the electronic key 2 is kept high until unnecessary. This is because there is an aim to reduce it. When the microcomputer 23 of the electronic key 2 makes a negative determination in the request determination after making a positive determination in the WAKE determination as described above, it lowers the reception sensitivity of the own key to the first reception sensitivity and activates the own key. To the WAKE signal reception standby state.

  Based on the above description, an example of output adjustment control by the verification control device 35 of the security device 3 and sensitivity adjustment control by the microcomputer 23 of the electronic key 2 will be described with reference to FIG.

  When the WAKE signal is periodically transmitted with the first transmission output from the security device 3 toward the smart communication area A32, when the electronic key 2 exists outside the smart communication area A32, the electronic key 2 is Therefore, the reception sensitivity of the electronic key 2 is set to the first reception sensitivity (before point P0). It should be noted that the door lock switch according to the above description is transmitted not only when the WAKE signal is periodically transmitted along with the execution of the first call control, but also when the WAKE signal is transmitted with the execution of the second call control. Even when the WAKE signal is transmitted irregularly triggered by the operation of the trigger switch as described above, the WAKE signal is transmitted with the first transmission output.

  When the holder of the electronic key 2 enters the smart communication area A32, a WAKE signal is received by the electronic key 2, the electronic key 2 is activated, and a WAKE determination is performed by the microcomputer 23 of the electronic key 2. When an affirmative determination is made in this WAKE determination, the reception sensitivity of the electronic key 2 is raised to the second reception sensitivity (point P1).

  When bi-directional communication is established between the electronic key 2 and the security device 3 in this way, an ACK signal is transmitted from the electronic key 2 and when this ACK signal is received by the security device 3, the security device The request signal is transmitted from 3 to the second transmission output. On the other hand, when an affirmative determination is made in the WAKE determination by the electronic key 2, the electronic key 2 enters a request signal reception standby state, and in this request signal reception standby state, the reception sensitivity of the electronic key 2 has a high sensitivity. Maintained with sensitivity. When the request signal is received by the electronic key 2, the request determination is performed by the microcomputer 23 of the electronic key 2, and when the request determination is affirmative, the reception sensitivity of the electronic key 2 is the first reception sensitivity. Pulled down. Note that if the affirmative determination is not made in the request determination within a period from when the WAKE determination by the electronic key 2 is affirmed until a predetermined time elapses, the reception sensitivity of the electronic key 2 is lowered to the first reception sensitivity ( Point P2).

  In the present embodiment, the electronic key 2 corresponds to a “portable device”, the security device 3 corresponds to a “communication device”, and the security system 1 corresponds to a “communication system”. The WAKE signal transmitted from the security device 3 corresponds to a “call signal” transmitted from the security device 3 as a trigger signal for establishing bidirectional communication. On the other hand, the ACK signal transmitted from the electronic key 2 corresponds to a “response signal” for the WAKE signal. On the other hand, the request signal transmitted from the security device 3 corresponds to a “secondary signal” for the ACK signal. The ID code signal transmitted from the electronic key 2 corresponds to a “reply signal” for the request signal. The microcomputer 23 of the electronic key 2 corresponds to “sensitivity adjusting means” for setting the reception sensitivity of the own key, and also corresponds to “reception determining means” for performing WAKE determination and request determination. On the other hand, the collation control device 35 of the security device 3 corresponds to “output adjustment means” for setting the transmission output of the WAKE signal and the request signal.

As described above, according to the present embodiment, the following operational effects can be achieved.
(1) Before activation, the electronic key 2 waits for a WAKE signal with a first reception sensitivity lower than the second reception sensitivity. For this reason, in comparison with a configuration in which the WAKE signal is waited at a relatively high receiving sensitivity, such as waiting for a WAKE signal at the second receiving sensitivity, noise is generated for another signal different from the WAKE signal, that is, the electronic key 2. The erroneous activation of the electronic key 2 accompanying the reception of the signal is naturally suppressed. Therefore, erroneous activation of the electronic key 2 due to so-called noise can be reduced. In the present embodiment, even if the electronic key 2 is set to low sensitivity, transmission is performed for the purpose of differentiation from the noise in order to ensure that the electronic key 2 is activated when the WAKE signal is received. A configuration is adopted in which a WAKE signal having a large output is transmitted from the security device 3, thereby preparing an environment in which the electronic key 2 can be easily activated even with low sensitivity.

  (2) The reception sensitivity is raised to the second reception sensitivity only when a normal WAKE signal is received. For example, when the electronic key 2 is erroneously activated due to reception of noise, the reception sensitivity is set to the second reception sensitivity. While maintaining the first reception sensitivity without raising the reception sensitivity, the electronic key 2 is shifted from the activated state to the WAKE signal reception standby state. Here, in a configuration different from the present configuration, that is, in a configuration in which the reception sensitivity is raised to the second reception sensitivity without exception even when the portable device is activated not only with the regular WAKE signal but also with the reception of noise, As the period set for the second reception sensitivity increases, noise is easily received based on the so-called high reception sensitivity due to the second reception sensitivity. In this regard, in this configuration, since the device for reducing the period during which the reception sensitivity is set to the second reception sensitivity is elaborated, it is difficult to receive noise in comparison with the other configuration, that is, the noise. Even if the key reaches the electronic key 2, it is difficult to activate the electronic key 2, so that the erroneous activation of the electronic key 2 due to noise can be reduced.

  (3) The reception sensitivity is raised to the second reception sensitivity only when the normal WAKE signal is received, and the ACK signal for the WAKE signal is received from the electronic key 2 only when the normal WAKE signal is received in this way. I am trying to send it. For this reason, even if the electronic key 2 is erroneously activated due to noise reception, an ACK signal is not transmitted from the electronic key 2, and thus the electronic key 2 is transmitted by an operation of transmitting an ACK signal accompanying noise reception. Power consumption can be eliminated. Accordingly, in consideration of the fact that the electronic key 2 performs the ACK signal transmission operation using the power stored in the button-type battery, it is possible to suppress the consumption of the battery power, and thereby the frequency of battery replacement. Can be reduced. Therefore, the user's economic burden can be reduced.

  (4) Since the WAKE signal is transmitted from the security device 3 with the first transmission output having a larger transmission output than the second transmission output in order to establish bidirectional communication, this WAKE signal is received by the electronic key 2 In other words, an environment in which the electronic key 2 can be easily activated even with low sensitivity is provided. When the ACK signal from the electronic key 2 is received by the security device 3, a request signal is transmitted from the security device 3 with the second transmission output. In this way, only the WAKE signal, that is, the trigger signal for establishing the bidirectional communication is transmitted with a large transmission output, and the transmission output of the signal after the establishment of communication, such as a request signal, is lowered. Therefore, in comparison with the configuration in which the transmission operation is performed with a relatively large transmission output even after the communication is established, such as transmitting the request signal with the first transmission output, the security device 3 side The power consumption associated with the transmission operation at can be reduced. For example, when the security system 1 is applied to a vehicle as in the present embodiment, consumption of battery power mounted on the vehicle can be suppressed. In this embodiment, in order to ensure that a request signal with a small transmission output is received by the electronic key 2, the reception sensitivity of the electronic key 2 is set to a relatively high reception sensitivity like the second reception sensitivity. A configuration is adopted in which an environment in which a request signal with a small transmission output is easily received is prepared.

  (5) The reception sensitivity of the electronic key 2 is set to the second reception sensitivity once in response to the reception of the noise worthy of the normal WAKE signal, and the normal request signal is not received within a predetermined period. In this case, the reception sensitivity of the electronic key 2 is lowered to the first reception sensitivity that is lower than the second reception sensitivity. In other words, even when the electronic key 2 is activated due to noise, the reception sensitivity of the electronic key 2 is immediately reduced when the activation is identified as noise, and the electronic key 2 is moved from the activated state to WAKE. A transition is made to a signal reception standby state. Therefore, by slowing down the reception sensitivity of the electronic key 2 in the WAKE signal reception standby state, erroneous activation of the electronic key 2 due to noise is naturally suppressed, and as a result, erroneous activation of the electronic key 2 due to noise can be reduced. .

  (6) Assuming that the reception sensitivity is raised to the second reception sensitivity when a regular WAKE signal is received, the following is performed. That is, the reception sensitivity is maintained at the second reception sensitivity only when a normal request signal is received within a predetermined period, and the ID code for the request signal is only received when the normal request signal is received in this way. A signal is transmitted from the electronic key 2. For this reason, even if the electronic key 2 is erroneously activated due to noise reception, the ID code signal is not transmitted from the electronic key 2, and thus the electronic key is transmitted by the operation of transmitting the ID code signal accompanying noise reception. 2 power consumption can be eliminated. Therefore, in consideration of the fact that the electronic key 2 performs the operation of transmitting the ID code signal using the power stored in the button type battery, it is possible to suppress the consumption of the battery power. The frequency can be reduced. Therefore, the user's economic burden can be reduced.

  (7) It is possible to receive a WAKE signal by waiting for the WAKE signal with a minimum reception sensitivity that is sufficient to receive the WAKE signal. Of course, the low-sensitivity noise is not received because of the low sensitivity. The erroneous activation of the electronic key 2 can be reliably reduced.

  (8) It is sufficient to receive the request signal with the electronic key 2. In other words, the request signal can be received with the electronic key 2 by transmitting the request signal with the minimum transmission output. The power consumption associated with the operation is reduced, and thus the power saving of the security device 3 can be achieved.

In addition, the said embodiment can also be changed and actualized as follows.
In the configuration according to the embodiment, when a positive determination is made in the request determination by the electronic key 2, the reception sensitivity of the electronic key 2 is immediately reduced from the second reception sensitivity. However, after a positive determination is made in the request determination, The period until the predetermined time elapses may be maintained at the second sensitivity with high sensitivity. With this configuration, when the ID code signal transmitted from the electronic key 2 is not normally received by the security device 3 due to the positive determination in the request determination, the request signal is again transmitted from the security device 3. Can be adapted to a system such as That is, the request signal due to the retry can be reliably received with the high second sensitivity, and the probability that the two-way communication between the electronic key 2 and the security device 3 can be completed to the end is achieved. Can be increased. Therefore, the “certain time” in the configuration according to this another example is defined as a time in consideration of the transmission operation by the retry for the transmission operation of the request signal on the security device 3 side. That is, it is defined as the time from when an affirmative determination is made in the WAKE determination until the timing at which the received signal related to the request signal due to the retry is to be input from the receiving circuit 22 to the microcomputer 23. The number of retries may be one time or a plurality of times, and the “certain time” may be defined as a time considering the request signal transmission operation by the last retry.

A configuration in which the reception sensitivity of the electronic key 2 is subdivided into three or more stages may be adopted.
-You may employ | adopt the structure which subdivides the transmission output of the security apparatus 3 into three steps or more.
-As an example of a communication system for a vehicle, in bidirectional communication, a WAKE signal is transmitted as a call signal from a communication device, and an ACK signal is transmitted from a portable device as a response signal to the WAKE signal. Then, a VEHICLE signal is transmitted from the communication device, and an ACK signal is transmitted from the portable device in response to this VEHICLE signal. A request signal is transmitted from the communication device in response to the ACK signal, and an ID code signal is transmitted from the portable device in response to the request signal. Here, the secondary signal in the present invention includes all signals other than the WAKE signal corresponding to the interrogation signal among the signals transmitted from the communication apparatus, that is, in the case of the above example, the VEHICLE signal and the request signal are second signals. It is included in the next signal.

  Here, the portable device performs the following VEHICLE determination following the WAKE determination and request determination according to the embodiment. In other words, the portable device has a regular time within a certain period of time after the affirmative determination in the WAKE determination, that is, until a certain time defined as the time until the VEHICLE signal is to be received by the portable device. It is determined whether the VEHICLE signal is received by the portable device. When the mobile device makes an affirmative determination in the VEHICLE determination, the mobile device maintains the reception sensitivity of the mobile device at the second reception sensitivity and transitions to a request signal reception standby state, while negatively determines in the VEHICLE determination. When the determination is made, the reception sensitivity of the portable device is lowered to a reception sensitivity lower than the second reception sensitivity, for example, the first reception sensitivity. Therefore, the ACK signal is transmitted from the portable device only when the regular VEHICLE signal is received as the secondary signal, and the ID code signal is transmitted from the portable device only when the regular request signal is received as the secondary signal. This makes it possible to reduce the power consumption of the portable device.

  ・ It is not limited to a portable device with a primary battery such as a button-type battery, but a rechargeable secondary battery is built in as a power source. The secondary battery supplies power and receives the WAKE signal from the ID code signal. The present invention may be embodied in a communication system including a portable device that performs various operations including a series of communication operations leading to transmission. In this case, when the power stored in the secondary battery is exhausted, the stored power is restored by charging the secondary battery. Even when the present invention is embodied in a communication system including the same, the power saving of the portable device is not changed, and in this case, the frequency of charging the secondary battery is reduced.

  The communication system according to the present invention is not limited to a vehicle security system, and may be embodied as a security system for buildings such as houses and stores. In the building security system, the resident of the building, that is, the user, possesses an electronic key such as the electronic key 2 configured as described above as a home key, and the security device 3 configured as described above. A security device is provided at the entrance door or the like. Then, a WAKE signal is transmitted from the security device to the smart communication area around the door. When this WAKE signal is received by the electronic key, an ACK signal is transmitted from the electronic key. Then, after the two-way communication is established in this way, when it is affirmed that a proper electronic key exists in the smart communication area through the key verification, the unlocking of the door by the security device is permitted. In some cases, the door is automatically opened on the condition that no person is present outdoors to realize the automatic door.

Next, a technical idea that can be grasped from the above embodiment and another example will be described.
(B) The communication system according to any one of claims 1 to 4, wherein the first reception sensitivity is defined as the lowest reception sensitivity among the reception sensitivities for the portable device that can receive the call signal. According to the same configuration, it is possible to receive the interrogation signal by waiting for the interrogation signal with a minimum reception sensitivity that is sufficient to receive the interrogation signal. The erroneous start-up of the portable device due to noise can be reliably reduced.

  (B) The second transmission output is defined as the smallest transmission output among the transmission outputs that can receive the secondary signal by the portable device. The communication system according to 1. According to this configuration, the secondary signal can be received by the portable device by transmitting the secondary signal with a minimum transmission output sufficient to receive the secondary signal by the portable device, and the transmission output is small. Therefore, the power consumption accompanying the transmission operation is reduced, so that the power saving of the communication device can be achieved.

  DESCRIPTION OF SYMBOLS 1 ... Security system (communication system), 2 ... Electronic key (portable machine), 3 ... Security apparatus (communication apparatus), 21 ... Reception antenna, 22 ... Reception circuit, 23 ... Microcomputer (sensitivity adjustment means, reception determination means), 23a ... memory, 24 ... transmission circuit, 25 ... transmission antenna, 31 ... transmission circuit, 32 ... transmission antenna, 33 ... reception antenna, 34 ... reception circuit, 35 ... collation control device (output adjustment means), 35a ... memory, A32 ... Smart communication area.

Claims (4)

In a communication system capable of two-way communication between a portable device owned by a user and a communication device,
A signal transmitted from the communication device as a trigger signal for establishing the bidirectional communication is defined as an interrogation signal, and a reception sensitivity capable of receiving the interrogation signal for the portable device is defined as a first reception sensitivity. ,
When the portable device is activated from a reception standby state of the call signal based on the first reception sensitivity, the portable device has a second reception sensitivity higher than the first reception sensitivity. A communication system comprising a sensitivity adjustment means for setting the reception sensitivity. The communication system according to claim 1,
The portable device includes reception determination means for determining whether or not the call signal is received by the portable device;
The sensitivity adjustment unit sets the reception sensitivity of the portable device to the second reception sensitivity when the reception determination unit determines that the call signal is received by the portable device. system. The communication system according to claim 1 or 2,
When the interrogation signal is received by the portable device, a response signal to the interrogation signal is transmitted from the portable device, and the transmission output of the interrogation signal for the communication device is defined as a first transmission output,
When the communication device receives the response signal in response to transmitting the interrogation signal at the first transmission output, the communication device transmits a secondary signal corresponding to the response signal from the first transmission output. A communication system characterized by comprising output adjusting means for transmitting with a second transmission output having a small transmission output. The communication system according to any one of claims 1 to 3,
In the bidirectional communication, when the interrogation signal is received by the portable device, a response signal for the interrogation signal is transmitted from the portable device, and when the response signal is received by the communication device, the communication device A secondary signal for the response signal is transmitted from the device,
The portable device includes a reception determination unit that determines whether a signal transmitted from the communication device in the bidirectional communication is received by the portable device;
The sensitivity adjustment unit is configured to receive the secondary signal from the reception determination unit within a period from when the reception determination unit determines that the call signal is received by the own portable device until a predetermined time elapses. When a negative determination is made that no reception has been received, the communication sensitivity of the portable device is set to a reception sensitivity lower than the second reception sensitivity.

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