JP2011089264A - Communication pattern switching device of electronic key system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication pattern switching device of an electronic key system, which sets a communication pattern of a communication master as a pattern best suited to a communication state and copes with even when a standard on the Radio Law is an issue in pattern switching. <P>SOLUTION: When a vehicle is in a parked state, a vehicle exterior transmitter 10 performs radio wave transmission by the communication pattern P1 setting high radio output V1 and a long time interval T1, and places priority on communication establishability. When an electronic key 2 makes an entry into the communication area of the vehicle exterior transmitter 10, the electronic key 2 receives a wake signal 21 so that vehicle exterior communication can be established. In this case, the vehicle exterior transmitter 10 switches the communication pattern of the radio wave transmission from the first communication pattern P1 to the second communication pattern P2. The second communication pattern P2 is set as the pattern setting a QP value identical with that of the first communication pattern P1 and setting low radio output V2 and a short time interval T2, placing priority on the responsiveness of the communication. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication pattern switching device for an electronic key system that performs ID verification using an ID code wirelessly transmitted from an electronic key.

  2. Description of the Related Art Conventionally, an electronic key system (see, for example, Patent Document 1) that performs ID verification by wirelessly transmitting a key-specific ID code to a vehicle has been used in many vehicles. In this electronic key system, a request signal is transmitted as an ID reply request from the vehicle, and ID verification is performed by an ID signal returned from the electronic key in response to the request signal. There is a key operation free system in which engine start is permitted or executed. The key operation free system is widely used as a highly convenient system because it does not require button operation with an electronic key.

  By the way, in a general key operation free system, if the systems are the same, the communication pattern 81 of the request signal is the same as shown in FIG. And the communication area of a request signal is set to the range according to the vehicle grade, respectively. Note that the communication pattern 81 is a parameter of a communication mode that is determined depending on what value the radio wave output 82 and the communication interval 83 of the request signal have.

JP 2005-262915 A

  However, in some cases, for example, there is a need to improve communication responsiveness by shortening the communication interval 83 of the communication pattern 81 in the request signal. As described above, if the communication interval 83 is shortened, the request signal is repeatedly transmitted in a short cycle. Therefore, as soon as the electronic key approaches the vehicle, communication is established, and the communication throughput is improved. Here, the standard of the Radio Law has a rule that the QP value (electric field strength) is kept within a certain value as an average value of radio wave output. However, there is a problem that the QP value does not satisfy the laws and regulations of the Radio Law simply by shortening the communication interval 83 in order to improve communication responsiveness.

  The object of the present invention is to set the communication pattern of the communication master to an optimum pattern according to the communication state, and to cope with this even if the standard of the Radio Law becomes a problem when switching patterns. It is an object of the present invention to provide a communication pattern switching device for an electronic key system.

  In order to solve the above problem, in the present invention, a request signal for returning an ID code is transmitted from the communication master, and ID verification is performed by an ID signal transmitted from the electronic key in response to the request signal. In a communication pattern switching device of an electronic key system that permits or executes device operation if verification is established, a determination unit that determines a communication state between the communication master and the electronic key, and a determination result of the determination unit And a changing means for switching a communication pattern to be taken when the communication master transmits a radio wave to a pattern corresponding to the communication state by changing the radio wave output and the communication interval while keeping the output average of the radio wave constant. The main point is that

  According to this configuration, the communication state of the electronic key with respect to the communication master is determined, and the radio wave output and the communication interval are changed in a state where the output average of the communication master's radio wave is kept constant. The communication pattern is set to a pattern according to the current communication state. For this reason, for example, a communication pattern that prioritizes communication establishment or a communication pattern that prioritizes responsiveness can be used, so that high functionality can be achieved as a system. Even if the communication pattern is changed according to the communication status, the average output of the radio wave is kept constant. For example, even if there is a limit to the average radio wave output by the Radio Law, etc. It becomes possible.

The gist of the present invention is that the average output of the radio wave is a QP value defined by the Radio Law.
According to this configuration, even if the communication pattern of the communication master at the time of radio wave transmission is switched to another pattern, the output average of the radio wave satisfies the QP value stipulated by the Radio Law, so the communication pattern can be changed without violating the Radio Law. Switching can be performed.

  In the present invention, the determining means includes key approaching presence / absence determining means for determining whether or not the electronic key is in an approaching state to the communication master, and the changing means is configured such that the electronic key is connected to the communication master. When the communication key of the communication master is at a position close to the communication master, the communication pattern of the communication master is a pattern in which the radio wave output is high and the communication interval is long. The communication pattern is set to a pattern in which the radio wave output is low and the communication interval is short.

  According to this configuration, if the electronic key is far from the communication master, priority is given to communication establishment, and ID verification is started more reliably. Priority is given to completing ID verification immediately. For this reason, communication can be executed in an optimal communication mode according to each situation, and ID verification can be established smoothly and reliably.

  In the present invention, the determination unit includes a noise presence / absence determination unit that determines whether noise is generated in the communication environment of the ID verification, and the change unit has noise in the communication environment less than an allowable value. In this case, the communication pattern of the communication master is set to a pattern in which the radio wave output is low and the communication interval is shortened, and when the noise in the communication environment is equal to or higher than an allowable value, the communication of the communication master The gist is to set the pattern to a communication pattern in which the radio wave output is high and the communication interval is long.

  According to this configuration, when the noise in the communication environment is less than the allowable value, priority is given to responsiveness, and ID collation is immediately started to complete. ID collation is surely started with priority. For this reason, since ID collation can be executed in an optimal communication mode according to each situation, ID collation can be more reliably established.

  According to the present invention, the communication pattern of the communication master can be set to an optimal pattern according to the communication state, and even if the radio wave standard becomes a problem when switching the pattern, it is possible to cope with this. Can do.

The block diagram which shows schematic structure of the key operation free system and communication pattern switching apparatus in one Embodiment. The signal figure which shows the pattern content of a 1st communication pattern. The signal diagram which shows the pattern content of a 2nd communication pattern. The timing chart which shows the communication operation | movement of communication outside a vehicle. The timing chart which shows communication operation when the noise environment at the time of in-vehicle communication is good. The timing chart which shows communication operation when the noise environment at the time of in-vehicle communication is bad. The signal diagram which shows the pattern content of the other communication pattern in another example. The signal diagram which shows an example of the communication pattern in the past.

Hereinafter, an embodiment of a communication pattern switching device for an electronic key system embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the vehicle 1 is provided with a key operation free system 3 that automatically executes ID (Identification) verification when the electronic key 2 approaches the vehicle 1. This key operation free system 3 includes a smart entry system in which a door lock is unlocked and unlocked in a series of door opening and closing operations without actually performing a key operation, and a push type engine installed in the vehicle. There is a one-push engine start system that can start the engine only by pressing the switch 4. The key operation free system 3 corresponds to an electronic key system.

  In this case, the vehicle 1 includes a key verification device 5 that performs ID verification with the electronic key 2, a door lock device 6 that manages a door lock operation, and an engine start device 7 that manages the operation of the engine. These are provided and connected by an in-vehicle bus 8. The key verification device 5 is provided with a verification ECU (Electronic Control Unit) 9 as a control unit of the device 5. In the memory (not shown) of the verification ECU 9, the ID code of the electronic key 2 that forms a pair with the vehicle 1 is registered. The verification ECU 9 receives an out-of-vehicle transmitter 10 that transmits LF (Low Frequency) radio waves outside the vehicle, an in-vehicle transmitter 11 that transmits LF radio waves into the vehicle, and UHF (Ultra High Frequency) radio waves. The vehicle tuner 12 is connected. The vehicle transmitter 10 and the vehicle transmitter 11 transmit a request signal Srq as an ID transmission request to the electronic key 2 by LF band radio waves, and try to establish so-called smart communication. The key verification device 5 corresponds to a communication master.

  On the other hand, the electronic key 2 is provided with a communication control unit 13 that performs overall control of the operation of the electronic key 2. An ID code is registered in the memory (not shown) of the communication control unit 13 as an ID unique to the key. The communication control unit 13 is connected to an LF receiver 14 capable of receiving LF band radio waves and a UHF transmitter 15 capable of transmitting UHF band radio waves.

  When the request signal Srq is intermittently transmitted from the outside transmitter 10 and the electronic key 2 enters the outside communication area of the request signal Srq, the electronic key 2 responds to the request signal Srq and receives the ID signal Sid. Reply with UHF band radio waves. The ID signal Sid includes the ID code of the electronic key 2. When the vehicle tuner 12 receives the ID signal Sid and the smart communication outside the vehicle (external communication) is established, the verification ECU 9 executes external verification as ID verification (smart verification). And if this outside vehicle collation is materialized, door lock locking / unlocking by the door lock device 6 is permitted or executed.

  Further, when it is detected by a courtesy switch or the like that the driver gets on, for example, the in-vehicle transmitter 11 starts transmitting the request signal Srq instead of the out-of-vehicle transmitter 10. At this time, when smart communication (in-vehicle communication) is established by entering the in-vehicle communication area of the in-vehicle transmitter 11, the verification ECU 9 executes in-vehicle verification as ID verification (smart verification). And if this in-vehicle collation is materialized, the power supply transition operation and engine starting operation by the engine switch 4 (engine starting device 7) will be permitted.

  The vehicle 1 is provided with a communication pattern switching device 16 that switches the communication pattern of the request signal Srq according to the communication status of smart communication. By the way, in the request signal Srq, as shown in FIGS. 2 and 3, a communication pattern P is set as a specific waveform of radio waves. With the communication pattern P, for example, when a batch data unit transmitted as the request signal Srq is the communication unit data 17, the radio wave output (peak value) V of the communication unit data 17 or two continuous communication unit data 17. , 17 indicates what value the communication interval (communication cycle) T is set to. The communication pattern switching device 16 switches the communication pattern P by changing the radio wave output V and the communication interval T.

  By the way, in the standard of the Radio Law, there is a provision that the average value of the radio wave output V over a plurality of communication unit data 17, that is, the QP value must be kept below a certain value. Therefore, in order to fly the request signal Srq over a wide area, the QP value of the communication pattern P is set to the maximum value (maximum allowable value) defined by the Radio Law. Each of the communication unit data 17 is constructed from, for example, a burst signal 18 that stabilizes the radio wave reception state and a data group 19 that is actual data contents to be sent to the communication partner. The QP value corresponds to the radio wave output average.

  In this case, as shown in FIG. 1, the verification ECU 9 is provided with an out-of-vehicle communication state determination unit 20 that determines the communication state of out-of-vehicle communication. The vehicle exterior communication state determination unit 20 determines whether or not the electronic key 2 possessed by the user is approaching the vehicle. For example, in response to the wake signal 21 that is initially issued in the request signal Srq, the electronic key 2 When 2 confirms that the response ACK signal 22 has been returned, it is determined that the electronic key 2 is approaching the vehicle 1. In addition, the vehicle exterior communication state determination part 20 comprises a determination means and a key approach presence determination means.

  The verification ECU 9 is provided with an in-vehicle communication state determination unit 23 that determines the communication state of in-vehicle communication. The in-vehicle communication state determination unit 23 determines whether or not noise is generated in the in-vehicle communication environment. For example, in-vehicle communication is established when it is confirmed by the courtesy switch that the user has boarded the vehicle. Whether or not the noise is less than the allowable value or greater than the allowable value is determined. Then, the in-vehicle communication state determination unit 23 determines that the in-vehicle noise environment is bad when it is confirmed that the in-vehicle collation is not established within a certain time limit even though the user can confirm that the user has boarded. . The in-vehicle communication state determination unit 23 constitutes determination means and noise presence / absence determination means.

  The verification ECU 9 is provided with a communication pattern switching execution unit 24 that switches the communication pattern P of the request signal Srq based on the determination results of the in-vehicle communication state determination unit 20 and the in-vehicle communication state determination unit 23. When the communication pattern switching execution unit 24 confirms that the user has not approached the vehicle 1 from the determination result of the vehicle exterior communication state determination unit 20, the communication pattern P of the request signal Srq is long instead of the high radio wave output V1. The first communication pattern P1 (see FIG. 2) is set to the communication interval T1. By so doing, the request signal Srq is transmitted with priority given to the output intensity, so that high communication feasibility is ensured. The communication pattern switching execution unit 24 corresponds to a changing unit.

  When the communication pattern switching execution unit 24 confirms that the user has approached the vehicle 1 from the determination result of the vehicle exterior communication state determination unit 20, the communication pattern P of the request signal Srq is set to the same QP as the first communication pattern P1. While maintaining the value, the second communication pattern P2 (see FIG. 3) is set to a low radio wave output V2 instead of the short communication interval T2. That is, the second communication pattern P2 has the same QP value by reducing the radio wave output V while shortening the communication interval T with respect to the first communication pattern P1. In this case, since the request signal Srq is repeatedly transmitted in a short cycle, the responsiveness of smart communication is improved.

  The communication pattern switching execution unit 24 also switches the communication pattern P of the request signal Srq based on the determination result of the in-vehicle communication state determination unit 23. When the communication pattern switching execution unit 24 confirms that the in-vehicle noise environment is good from the determination result of the in-vehicle communication state determination unit 23, the communication pattern switching execution unit 24 causes the request signal Srq to be transmitted in the second communication pattern P2 and prioritizes smart communication responsiveness. When the communication pattern switching execution unit 24 confirms that the in-vehicle noise environment is bad from the determination result of the in-vehicle communication state determination unit 23, the communication pattern switching execution unit 24 causes the request signal Srq to be transmitted in the first communication pattern P1 and prioritizes communication establishment.

Next, the communication operation of the key operation free system 3 of this example will be described with reference to FIGS.
First, as shown in FIG. 4, a specific example of the communication operation of the external communication will be described. When the vehicle 1 is parked, the verification ECU 9 intermittently transmits the wake signal 21 by the LF band radio wave in order to switch the electronic key 2 in the power-off state to the activated state. The wake signal 21 is transmitted with a first communication pattern P1 as shown in FIG. Therefore, the wake signal 21 is repeatedly transmitted with a pattern of a high radio wave output V1 and a long communication interval T1. In this case, communication establishment is prioritized as much as the radio wave output V is set higher.

  When the electronic key 2 enters the outside communication area of the outside transmitter 10 and receives the wake signal 21, the electronic key 2 is switched to the power-on state. Then, the electronic key 2 returns an ACK signal 22 by a UHF band radio wave to notify the vehicle 1 that the power is turned on.

  When the outside communication state determination unit 20 receives the ACK signal 22 within a predetermined time after the wake signal 21 is transmitted from the outside transmitter 10, the outside communication state determination unit 20 recognizes that the electronic key 2 is approaching the vehicle 1, and accordingly. Is output to the communication pattern switching execution unit 24. When the communication pattern switching execution unit 24 recognizes that the electronic key 2 is approaching the vehicle 1, the communication pattern switching execution unit 24 switches the subsequent communication outside the vehicle from the first communication pattern P <b> 1 to the second communication pattern P <b> 2. For this reason, the on-vehicle transmitter 10 executes the following on-vehicle communication with the pattern of the low radio wave output V2 and the short communication interval T2 under the same condition as when the QP value is the wake signal 21. In this case, communication responsiveness is prioritized as much as the communication interval T is set short.

  When the verification ECU 9 receives the ACK signal 22 after the transmission of the wake signal 21, the verification ECU 9 transmits the vehicle ID 25 from the outside transmitter 10 by radio waves in the LF band. At this time, since the vehicle ID 25 is transmitted by the second communication pattern P2, the radio wave output V is kept low. The vehicle ID 25 is a kind of vehicle ID determined for each vehicle 1. The vehicle ID 25 is transmitted after the communication interval Tx that can satisfy the same QP value when the communication pattern P is switched from the transmission of the last wake signal 21.

  When receiving the vehicle ID 25, the electronic key 2 executes vehicle ID verification. When the electronic key 2 confirms that the collation is established, the electronic key 2 returns an ACK signal 26 by a radio wave in the UHF band.

  The verification ECU 9 recognizes that the electronic key 2 corresponding to the vehicle 1 exists in the vicinity of the vehicle when the acknowledgment signal 26 is received within a predetermined time after the vehicle ID 25 is transmitted. When the verification ECU 9 confirms that vehicle ID verification has been established, the verification ECU 9 transmits a challenge 27 from the outside transmitter 10 by radio waves in the LF band. At this time, the challenge 27 is transmitted after a communication interval T2 has elapsed from the completion of transmission of the vehicle ID 25. The challenge 27 includes a key number for identifying which master key or subkey the electronic key 2 is and a challenge code used for challenge response authentication.

  When the electronic key 2 receives this challenge 27, the electronic key 2 performs key number verification using the key number included in the challenge 27. If the key number verification is established, the electronic key 2 calculates the response code by calculating the subsequent challenge code using its own encryption key. The electronic key 2 returns a response 28 including its own ID code and the calculated response code by a UHF band radio wave.

  When transmitting the challenge 27, the verification ECU 9 calculates the challenge code using its own encryption key and calculates the response code itself. When the verification ECU 9 receives the response 28 from the electronic key 2, the verification ECU 9 compares the response code included in the response 28 with the one obtained by the verification ECU 9 and performs response code verification. When the collation ECU 9 confirms that this collation is established, the collation ECU 9 collates the ID code included in the same response 28. If this ID code collation is also established, the collation ECU 9 regards the smart collation as being established. Thereby, the door lock is unlocked or executed.

  Next, as shown in FIG. 5, a specific example of communication operation when the noise environment is good in in-vehicle communication will be described. The verification ECU 9 transmits the wake signal 21 by the second communication pattern P2 during in-vehicle communication. For this reason, the wake signal 21 in the vehicle is repeatedly transmitted with a low radio wave output V2 and a short communication interval T2. In this example, the case where the noise environment is good is mentioned, so that the electronic key 2 entering the vehicle receives the wake signal 21 without any problem. When the electronic key 2 receives the wake signal 21 and takes a power-on state, the electronic key 2 returns an ack signal 22.

  The in-vehicle communication state determination unit 23 measures the elapsed time from when the in-vehicle transmitter 11 starts transmitting the wake signal 21, and recognizes that the noise environment is good if the ACK signal 22 can be received within the time limit. Is output to the communication pattern switching execution unit 24. When confirming that the noise environment in the vehicle is good, the communication pattern switching execution unit 24 causes the subsequent communication in the vehicle to be continuously executed in the second communication pattern P2. For this reason, the in-vehicle transmitter 11 executes subsequent in-vehicle communication with a low radio wave output V2 and a short communication interval T2 as in the case of transmission of the wake signal 21. In this case, communication responsiveness is prioritized as much as the communication interval T is set short.

  Therefore, the vehicle ID 25 is transmitted from the vehicle 1 with a low radio wave output V2 after a short communication interval T2 after the last wake signal 21 is transmitted. Further, when the ACK signal 26 is received from the electronic key 2 within a certain time after the vehicle ID 25 is transmitted, the challenge 27 is transmitted with a low radio wave output V2 after a short communication interval T2 after the vehicle ID 25 is transmitted. Then, when it is confirmed that the verification is established and the in-vehicle verification is established, door locking / unlocking is permitted or executed.

  Next, as shown in FIG. 6, a specific example of communication operation when the noise environment is bad in in-vehicle communication will be described. If the in-vehicle communication state determination unit 23 cannot receive the ACK signal 22 within the time limit after the in-vehicle transmitter 11 starts to transmit the wake signal 21, the in-vehicle communication state determination unit 23 recognizes that the noise environment is bad and executes communication pattern switching. To the unit 24. When recognizing that the noise environment in the vehicle is bad, the communication pattern switching execution unit 24 switches the subsequent in-vehicle communication from the second communication pattern P2 to the first communication pattern P1. For this reason, the in-vehicle transmitter 11 executes the subsequent in-vehicle communication with the pattern of the high radio wave output V1 and the long communication interval T1 under the same QP value as that of the communication so far. In this case, communication establishment is prioritized as much as the radio wave output V is set higher.

  In this case, the verification ECU 9 switches the wake signal 21 to the first communication pattern P1 and transmits it. That is, the wake signal 21 is transmitted with a high radio wave output V1 and a long communication interval T1 under the same QP value as before. The first wake signal 21 when the second communication pattern P2 is reached is transmitted through a communication interval Tx that satisfies the same QP value when the communication pattern P is switched.

  At this time, since the wake signal 21 is transmitted with a high radio wave output V1, the wake signal 21 can easily reach the electronic key 2 even if noise exists in the in-vehicle communication environment, and as a result, the electronic key 2 is activated. It becomes possible. When the verification ECU 9 confirms that the electronic key 2 is turned on, the vehicle ID 25 and the challenge 27 are transmitted with the first communication pattern P1, that is, the high radio wave output V1 and the long communication interval T1, and the in-vehicle verification is established. If this is confirmed, the power switch operation and the engine start operation by the engine switch 4 are permitted.

  Therefore, in this example, when the electronic key 2 takes a position far from the vehicle 1 during external communication, the communication pattern P of the external transmitter 10 is set as the first communication pattern P1, giving priority to communication establishment, When the key 2 takes a position approaching the vehicle 1, the communication pattern P of the outside transmitter 10 is switched to the second communication pattern P2 to give priority to responsiveness. Also, during in-vehicle communication, when the in-vehicle noise environment is good, priority is given to responsiveness with the communication pattern P of the in-vehicle transmitter 11 as the second communication pattern P2, and when the in-vehicle noise environment is bad, the communication pattern P of the in-vehicle transmitter 11 Is switched to the first communication pattern P1 to prioritize communication establishment.

  Therefore, since the communication pattern P of the vehicle transmitter 10 and the vehicle transmitter 11 is set to an optimum pattern corresponding to the communication state at that time, the smart verification can be performed smoothly and reliably. In addition, when switching the communication pattern P of the vehicle transmitter 10 or the vehicle transmitter 11, the radio wave output V and the communication interval T of the transmission radio wave are changed while satisfying the specified values of the radio wave method. It is possible to execute ID collation with a communication pattern P that matches the current communication state without violating regulations.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) The communication pattern P of the in-vehicle transmitter 10 and the in-vehicle transmitter 11 is switched according to the communication state (presence / absence of electronic key approach outside the vehicle, presence / absence of noise in the vehicle). When changing the radio wave output V of 11 or the communication interval T, these values are set to other values under the same QP value. For this reason, since ID collation can be performed with the optimal communication pattern P while satisfying the radio law, ID collation can be performed smoothly and reliably without violating the radio law.

  (2) When the radio wave output V and the communication interval T are changed when the communication pattern P is switched, these values are set so that the QP values are the same before and after the pattern switching. Therefore, even if the communication pattern P is changed to another pattern, since the QP value satisfies the radio wave law, the communication pattern P can be switched without violating the radio wave law.

  (3) When the electronic key 2 is not near the vehicle 1 when the vehicle 1 is parked, the communication pattern P of the external transmitter 10 is set as the first communication pattern P1 to prioritize communication establishment and more reliable ID verification. Try to start. Further, when the electronic key 2 approaches the vehicle 1 and the electronic key 2 is activated by the wake signal 21 from the vehicle 1 to establish communication outside the vehicle, the communication pattern P of the vehicle outside transmitter 10 is switched to the second communication pattern P2. Give priority to responsiveness and complete external verification immediately. For this reason, since it is possible to perform vehicle exterior communication with the optimal communication pattern P according to each condition, vehicle exterior verification can be established smoothly and reliably.

  (4) When the noise is less than the permissible value in the communication environment of in-vehicle communication, that is, the in-vehicle noise environment is good, the communication pattern P of the in-vehicle transmitter 11 is set to the second communication pattern P2 to give priority to responsiveness. Verification can be immediately completed from start to completion. Further, when the noise is above the allowable value in the communication environment of the in-vehicle communication, that is, the in-vehicle noise environment is bad, the communication pattern P of the in-vehicle transmitter 11 is set to the first communication pattern P1 to prioritize communication establishment. Matching can be performed more reliably. For this reason, since it becomes possible to perform in-vehicle collation with the optimal communication pattern P according to the presence or absence of noise, in-vehicle collation can be more reliably established.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
As shown in FIG. 7, the communication pattern P may be a third communication pattern P in which communication unit data 17a having a high radio wave output V1 and communication unit data 17b having a low radio wave output V2 are transmitted alternately. . Needless to say, the QP value of the third communication pattern P3 is the same as that of the communication pattern P before switching.

  The determination means is not limited to the in-vehicle communication state determination unit 20 that checks whether the electronic key 2 is approaching outside the vehicle or the in-vehicle communication state determination unit 23 that checks whether noise is generated in the vehicle. For example, the received signal strength of radio waves in the vehicle 1 may be monitored as the communication state, and the communication pattern P may be switched according to the received signal strength.

The determination unit may receive information related to the communication state from the electronic key 2 and grasp the communication state from the information.
The communication pattern P is not limited to the two patterns of the first communication pattern P1 and the second communication pattern P2, and may be set to 3 patterns or more, for example.

  -Keeping the radio wave output average constant is not limited to maintaining the QP value of the Radio Law, but the point is that the average output can be the same value before or after pattern switching, or the value below the Radio Law. That's fine.

  The determination of whether or not the key is approaching is not limited to being performed outside the vehicle, and may be performed inside the vehicle, for example. That is, the pattern switching format at the time of external communication may be applied to in-vehicle communication. Further, the pattern switching format at the time of communication outside the vehicle may be executed both inside and outside the vehicle.

  The determination of the presence or absence of noise is not limited to being performed inside the vehicle, and may be performed outside the vehicle, for example. That is, pattern switching during in-vehicle communication may be applied to out-of-vehicle communication. In addition, when looking at the presence or absence of noise outside the vehicle, for example, the door handle knob on the outside of the vehicle is touch-operated to unlock the door lock, or the lock button of the handle knob on the outside of the vehicle is pushed to lock the door lock, An example of determining that there is noise due to the fact that the outside-vehicle verification is not started is given. Further, this pattern switching format during in-vehicle communication may be executed both inside and outside the vehicle.

The radio wave output V is not limited to the peak value of the output, and the main point is that it includes parameters relating to the strength of the radio wave in a broad sense.
The key operation free system 3 is not limited to different frequencies for the forward communication (vehicle 1 → electronic key 2) and the backward communication (electronic key 2 → vehicle 1), and the same frequency may be used for the forward communication and the backward communication. Good.

-The frequency of the radio wave used in the key operation free system 3 is not limited to the LF band or the UHF band, but may be a frequency in another band.
The electronic key system mounted on the vehicle 1 is not limited to the key operation free system 3, for example, a wireless key system for operating an in-vehicle device by remote operation by button operation of the electronic key 2, or a transponder ( An immobilizer system that performs ID collation by an ID tag) may be included.

-The 1st communication pattern P1 and the 2nd communication pattern P2 are not limited to taking the same pattern content by the inside of a vehicle, and the vehicle exterior, The content may differ by the vehicle interior and the vehicle exterior.
The wake signal 21, the vehicle ID 25, and the challenge 27 are not limited to being transmitted in time series, but may be transmitted to the electronic key 2 at one time, for example.

The communication pattern switching device 16 is not limited to being mounted only on the vehicle 1, and may be mounted on other equipment such as a house, equipment, device, or the like.
Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.

  (A) In Claims 3 and 4, the communication master is installed in a communication target that can go in and out of the room, and the key approaching presence / absence determining means is configured such that the electronic key approaches the communication target outside the communication target room. It is determined whether or not. According to this configuration, when the electronic key is far from the communication target, priority is given to the establishment of communication between the two parties, so ID verification is started more reliably. Further, when the electronic key approaches the communication target, priority is given to the responsiveness between the two parties, so that the ID verification in the start state is immediately completed. Therefore, ID verification can be established smoothly and reliably.

  (B) The communication master according to any one of claims 3 and 4 and the technical idea (A), wherein the communication master is installed in a communication target that can enter and exit indoors, and the noise presence / absence determining means It is determined whether or not noise is generated. According to this configuration, when the electronic key is located in the communication target room, it is possible to more reliably establish ID verification even if noise is generated in the indoor communication environment.

  DESCRIPTION OF SYMBOLS 2 ... Electronic key, 3 ... Key operation free system as an electronic key system, 5 ... Key collation apparatus as communication master, 16 ... Communication pattern switching apparatus, 20 ... Determination means, Key approach existence determination means Determining section, 23 ... determining means, in-vehicle communication state determining section constituting noise presence / absence determining section, 24 ... communication pattern switching execution section as changing means, Srq ... request signal, Sid ... ID signal, P (P1-P3) ... Communication pattern, V (V1, V2) ... radio wave output, T (T1, T2, Tx) ... communication interval.

Claims (4)

An electronic device that transmits a request signal for returning an ID code from the communication master, executes ID verification based on the ID signal transmitted from the electronic key in response to the request signal, and permits or executes device operation if the ID verification is established. In the communication pattern switching device of the key system,
Determining means for determining a communication state between the communication master and the electronic key;
Based on the determination result of the determination means, by changing the radio wave output and the communication interval while keeping the output average of the radio wave constant, the communication pattern taken when the communication master transmits the radio wave according to the communication state A communication pattern switching device for an electronic key system, comprising: a changing means for switching to another pattern.   The communication pattern switching device for an electronic key system according to claim 1, wherein the output average of the radio wave is a QP value defined by the Radio Law. The determination means includes key approach presence / absence determination means for determining whether or not the electronic key is in an approach state to the communication master.
When the electronic key is at a position far from the communication master, the changing unit sets the communication pattern of the communication master to a pattern in which the radio wave output is high and the communication interval is long. 3. The communication pattern of the communication master is set to a pattern in which the radio wave output is low and the communication interval is short when the position is close to the communication master. Communication key switching device for electronic key system. The determination unit includes a noise presence / absence determination unit that determines whether noise is generated in a communication environment of the ID verification,
The changing means sets the communication pattern of the communication master to a pattern in which the radio wave output is low and the communication interval is short when noise in the communication environment is less than an allowable value, The communication pattern of the communication master is set to a communication pattern in which the radio wave output is high and the communication interval is long when the noise of the communication is greater than or equal to an allowable value. A communication pattern switching device for an electronic key system according to claim 1.

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