JP6702840B2 - Wireless communication correctness determination system - Google Patents

Description

The present invention relates to a wireless communication correctness determination system.

2. Description of the Related Art Conventionally, there is known an electronic key system that performs ID verification by wireless communication between an electronic key (portable device) and a vehicle. In such an electronic key system, when the electronic key receives a request transmitted from the vehicle, the electronic key automatically returns an ID code to the vehicle in response to the request. When the ID verification is established outside the vehicle, locking and unlocking of the door is permitted, and when the ID verification is established inside the vehicle, the engine start is permitted.

By the way, in such an electronic key system, there is an illegal act using a repeater (see Patent Document 1, etc.) as an illegal act attempting to establish ID verification without depending on the user's intention. This fraudulent act is, for example, an act of connecting the electronic key to the vehicle by a plurality of relays to relay radio waves when the electronic key is located far from the vehicle to establish communication between the two. There is a possibility that the door may be unlocked and the engine may be started illegally by the ID verification being established without the user's knowledge due to an illegal act using a repeater by a third party.

For this reason, as disclosed in Patent Document 2, there is one that determines whether or not the communication is regular communication based on the RSSI (received signal strength) of the radio wave used for communication between the vehicle and the electronic key. A method of determining whether the communication is regular communication using the RSSI of the radio wave includes, for example, the time change of the RSSI of the radio wave from the vehicle to the electronic key and the time change of the RSSI of the radio wave from the electronic key to the vehicle. If the two do not match, it is determined that this two-way communication is not regular communication. Accordingly, even when the radio waves of the bidirectional communication are relayed, it is possible to determine whether or not the bidirectional communication is the regular communication by using the RSSI of the radio waves of the bidirectional communication.

JP, 2006-161545, A JP, 2011-25714, A

By the way, the bidirectional communication between the vehicle and the electronic key is started when the start signal is transmitted from the vehicle to the electronic key. This start signal may also be sent to an electronic key that is located far away from the vehicle by passing a plurality of repeaters between the vehicle and the electronic key. In this respect, in the method of determining whether or not the communication is regular communication based on the degree of coincidence of the time change of the RSSI of the radio waves of the two-way communication, it is possible to determine whether or not the two-way communication is regular communication, but the bidirectional communication starts It was difficult to determine whether or not the start signal before being sent is normal communication.

It is an object of the present invention to provide a wireless communication correctness determination system capable of detecting unauthorized communication of a start signal transmitted before bidirectional communication.

In a wireless communication correctness determination system capable of achieving the above object, at least one of a first communication unit and a second communication unit that wirelessly communicate with each other is movable, and the first communication unit and the second communication unit are movable. Between the first communication section and the second communication section, triggered by a start signal transmitted to the first communication section or from the second communication section to the first communication section. A wireless communication correctness determination system for determining the correctness of bidirectional communication performed, wherein the first communication unit calculates a first received signal strength that is a received signal strength of a radio wave from the second communication unit. A first reception signal strength calculation unit for transmitting the information of the first reception signal strength calculated by the first reception signal strength calculation unit to the second communication unit, and the second communication. The unit receives a second received signal strength calculation unit that calculates a second received signal strength that is the received signal strength of the radio wave transmitted from the first communication unit, and the first received signal strength information. The time change of the first received signal strength based on the first received signal strength obtained by the above, and the time change of the second received signal strength calculated by the second received signal strength calculation unit. And a calculation unit that calculates the first received signal strength and the second received signal strength during the two-way communication based on the time change of the first received signal strength and the time change of the second received signal strength. When it is determined that the signal strength has not changed, the determination unit determines that the start signal is due to unauthorized communication.

According to this configuration, the determination unit determines whether the first communication unit and the second communication unit are based on the time change of the first received signal strength and the time change of the second received signal strength calculated by the calculation unit. It is possible to determine that at least one of them, which is movable, is in a stationary state, and based on the determination result, it can be determined whether or not the start signal is illegal communication.

For example, when the first communication section and the second communication section are close to each other, the closer the first communication section and the second communication section are, the larger the first received signal strength and the second received signal strength are. When the two communication units are separated from each other, the first received signal strength and the second received signal strength become smaller as the distance increases, so that the first received signal strength changes with time and the second received signal strength changes. The change in intensity over time should change. When the time change of the first received signal strength and the time change of the second received signal strength do not change, it is considered that the first communication unit and the second communication unit are stationary. In order for the first communication unit and the second communication unit to perform wireless communication with each other, the first communication unit and the second communication unit must be in the extent that the first communication unit or the second communication unit can receive the start signal. If the first communication unit and the second communication unit continue to be stationary, even though the communication unit of the second communication unit needs to be close to each other, it is considered that the start signal is illegally extended by the relay device or the like. .. Therefore, bidirectional communication between the first communication unit and the second communication unit is used to determine the stationary state of the first communication unit and the second communication unit, and thus the start signal is illegally It can be determined that unauthorized communication such as extension is being performed.

In the above wireless communication correctness determination system, the determination unit may change the first received signal strength with time during bidirectional communication performed between the first communication unit and the second communication unit. When the time change of the second received signal strength changes even once, it is determined that the start signal is normal communication, and the time change of the first received signal strength and the time change of the second received signal strength. Is not changed at all, it is preferable to determine that the start signal is due to unauthorized communication.

According to this configuration, for example, the first communication unit and the second communication unit are stationary after the first communication unit or the second communication unit receives the start signal, so that the first received signal strength changes with time. Even when the time variation of the second received signal strength does not change for a certain period of time, the first received signal is received at least once after the first communication unit or the second communication unit receives the start signal. If the time change of the intensity and the time change of the second received signal intensity are changed, it is determined that the start signal is regular communication. Therefore, even if the first communication unit or the second communication unit is stationary after receiving the start signal, it can be more accurately determined that the start signal is the normal communication.

According to the wireless communication correctness determination system of the present invention, it is possible to detect unauthorized communication of the start signal transmitted before the bidirectional communication.

The block diagram which shows the structure of a wireless communication correctness determination system. The flowchart of the communication correctness determination of the wireless communication correctness determination system in smart communication. The timing chart which shows the communication sequence of smart communication. Explanatory drawing which shows the outline of the illegal communication using a repeater. (A), (b) is a graph which shows the time change of the received signal strength of communication by the side of a vehicle, and the time change of the received signal strength of communication of the key side.

An embodiment of the wireless communication correctness determination system will be described below.
As shown in FIG. 1, there is an electronic key system 3 that performs ID verification by wirelessly communicating between a vehicle 1 and an electronic key 2. An electronic key ID is written and stored in the electronic key 2 as an ID unique to the key. The electronic key system 3 of the present embodiment is a key operation-free system that performs ID collation with the electronic key 2 through narrow area communication (two-way communication) triggered by wide area communication (starting signal) from the vehicle 1.

The vehicle 1 includes a verification ECU (Electronic Control Unit) 4 that performs ID verification, a body ECU 5 that manages driving of on-vehicle electrical components such as the door lock device 6, and an engine ECU 7 that controls an engine 8. The body ECU 5 switches the locking/unlocking of the vehicle door by controlling the operation of the door lock device 6 provided on the vehicle door. The body ECU 5 and the engine ECU 7 are electrically connected to each other through a communication line L inside the vehicle. As the communication line L, for example, CAN (Controller Area Network) is used. The verification ECU 4 stores the electronic key ID of the electronic key 2 registered in the vehicle 1. The vehicle 1 includes an LF transmitter 10 that transmits radio waves in the LF (Low Frequency) band inside and outside the vehicle, and a UHF transmitter/receiver 11 that transmits and receives radio waves in the UHF (Ultra High Frequency) band inside and outside the vehicle. An LF transmission unit 10 and a UHF transmission/reception unit 11 are connected to the verification ECU 4. The UHF transmission/reception unit 11 attempts to establish communication with the electronic key 2 by transmitting a request signal as an ID reply request to the electronic key 2 by a UHF band radio wave (UHF radio wave). The electronic key 2 corresponds to the first communication unit, and the verification ECU 4 corresponds to the second communication unit.

The electronic key 2 includes a key control unit 20 that controls the operation of the electronic key 2, an LF reception unit 30 that receives LF radio waves, and a UHF transmission/reception unit 31 that transmits/receives UHF radio waves. An LF receiver 30 and a UHF transmitter/receiver 31 are connected to the key controller 20. Further, in the key control unit 20, an “ID code” is written and stored in a memory (not shown) as an ID unique to the key. The UHF band radio waves transmitted from the UHF transmission/reception unit 11 of the vehicle 1 and the UHF band radio waves transmitted from the UHF transmission/reception unit 31 of the electronic key 2 have the same frequency.

When the electronic key 2 enters the LF radio wave area of the LF transmitter 10 (see FIG. 4) and communication is established between the vehicle 1 and the electronic key 2, smart verification by bidirectional UHF-UHF communication ( Outside vehicle ID verification) is started. The vehicle ID verification includes vehicle ID verification that authenticates the unique vehicle ID of the vehicle 1, challenge response authentication that uses an encryption key (authentication key), and electronic key ID verification that authenticates the electronic key ID. .. When the verification ECU 4 confirms that all of the ID verification and the authentication with the electronic key 2 located outside the vehicle are established, the verification ECU 4 regards the outside vehicle ID verification as successful, and permits or executes locking/unlocking of the vehicle door, for example. To do.

The verification ECU 4 executes the in-vehicle ID verification when the electronic key 2 enters the in-vehicle communication area of the UHF transmission/reception unit 11 after the outside-vehicle ID verification is established. When the verification ECU 4 confirms that the in-vehicle ID verification is established, the verification ECU 4 permits the transition of the vehicle power source and the start of the engine 8 by operating the engine switch 9.

The electronic key system 3 (wireless communication correctness determination system) has a function of suppressing unauthorized communication by a third party using a repeater, for example. The dishonest act using the repeater means that when the user who owns the electronic key 2 is far away from the vehicle 1, a third party who attempts to steal the vehicle uses the repeater to relay radio waves. Then, it is an act of illegally establishing communication between the vehicle 1 and the electronic key 2.

The key control unit 20 of the electronic key 2 is provided with a reception signal strength calculation unit 21 that calculates a reception signal strength (RSSI) of the received radio wave when the UHF band radio wave from the verification ECU 4 is received. When the UHF transmission/reception unit 31 receives a radio wave, the reception signal strength calculation unit 21 detects the amplitude of the received radio wave to calculate the first reception signal strength RSSI1. In addition, the reception signal strength calculation unit 21 calculates the reception signal strength RSSI1 of the UHF radio wave in association with the reception time each time the UHF radio wave is received from the vehicle 1.

In addition, the key control unit 20 of the electronic key 2 notifies the vehicle 1 of the reception signal strength RSSI1 calculated by the reception signal strength calculation unit 21 and the reception time associated with the first reception signal strength RSSI1 to the vehicle 1. A notification unit 22 is provided. When the electronic key 2 transmits various UHF radio waves in response to the inquiry of the vehicle 1, the reception signal strength notification unit 22 indicates the first reception signal strength RSSI1 in addition to the "ID code" and the "response code". The data containing the information is sent together.

The verification ECU 4 is provided with a received signal strength calculation unit 40, a calculation unit 41, and a communication correctness determination unit 42.
When receiving the UHF radio wave from the electronic key 2, the reception signal strength calculation unit 40 calculates the second reception signal strength RSSI2 which is the reception signal strength of the UHF radio wave. In addition, the reception signal strength calculation unit 40 calculates the reception signal strength RSSI2, which is the reception signal strength of the UHF radio wave, in association with the reception time each time the UHF radio wave is received from the vehicle 1.

The calculation unit 41 calculates the first reception signal strength RSSI1 calculated by the reception signal strength calculation unit 21 and the reception time thereof, and the second reception signal strength RSSI2 calculated by the reception signal strength calculation unit 40 and the reception time thereof. A temporal change (trajectory) of the first received signal strength RSSI1 and a temporal change (trajectory) of the second received signal strength RSSI2 are calculated.

The communication correctness determination unit 42 determines whether the communication between the vehicle 1 and the electronic key 2 is normal based on the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 calculated by the calculation unit 41. Determine whether it is communication.

Communication performed between the vehicle 1 (collation ECU 4) and the electronic key 2 will be described in detail with reference to FIGS. 2 and 3.
As shown in FIG. 2, when the vehicle is parked, the LF transmitter 10 intermittently transmits the wake signal S1 as an LF radio wave (LF radio wave) toward the outside of the vehicle. When the electronic key 2 receives the wake signal S1, the communication between the vehicle 1 and the electronic key 2 outside the vehicle is established. When the communication outside the vehicle is established, an ACK signal S2 is returned from the electronic key 2 by a UHF band radio wave (UHF radio wave).

When the verification ECU 4 receives the ACK signal S2 after transmitting the wake signal S1, it transmits the vehicle ID signal S3 by UHF radio waves. The vehicle ID signal S3 is a signal including a "vehicle ID" which is a unique ID of the vehicle 1. When the electronic key 2 receives the vehicle ID signal S3, the electronic key 2 collates the vehicle ID. When confirming that the vehicle ID verification is established, the electronic key 2 returns the ACK signal S4 by UHF radio waves again.

When the verification ECU 4 receives the ACK signal S4 after transmitting the vehicle ID signal S3, the collation ECU 4 transmits the first challenge signal CH1 (CH) by the UHF radio wave. The challenge signal CH1 includes a “challenge code” and a “key number”.

When the electronic key 2 receives the first challenge signal CH1, it first collates the key numbers. Next, when confirming that the key number collation is established, the electronic key 2 calculates the “response code” using the “challenge code” and its own encryption key. When the electronic key 2 receives the first challenge signal CH1, the electronic key 2 calculates the first received signal strength RSSIkey1 of the first challenge signal CH1 in association with the reception time of the first challenge signal CH. , The first response signal RE1 (RE) by the UHF radio wave that does not include the first received signal strength RSSIkey1 is transmitted. The response signal RE1 includes a "response code". Upon receiving the first response signal RE1, the verification ECU 4 calculates the second received signal strength RSSIcar1 at the time of receiving the first response signal RE1 in association with the reception time of the first response signal RE1, The second challenge signal CH2 by UHF radio wave is transmitted.

When the electronic key 2 receives the second challenge signal CH2, the electronic key 2 calculates the first received signal strength RSSIkey2 of the second challenge signal CH2 in association with the reception time of the second challenge signal CH2, and then The second response signal RE2 by the UHF radio wave which does not include the 1 reception signal strength RSSIkey2 is transmitted. When the verification ECU 4 receives the second response signal RE2, it calculates the second reception signal strength RSSIcar2 at the time of receiving the second response signal RE2 in association with the reception time of the second response signal RE2, A challenge signal (hereinafter not shown) from the third time onward by the UHF radio wave is transmitted.

When the electronic key 2 receives the n-th challenge signal CHn, the electronic key 2 calculates the first received signal strength RSSIkeyn of the n-th challenge signal CHn in association with the reception time of the n-th challenge signal CHn and then 1 Received signal strength The nth response signal REn by UHF radio waves not including RSSIkeyn is transmitted. When receiving the n-th response signal REn, the verification ECU 4 calculates the second reception signal strength RSSIcarn when the n-th response signal REn is received in association with the reception time of the n-th response signal REn.

After the bidirectional communication of the challenge signal CH and the response signal RE is repeated n times and the response signal REn of the nth time is transmitted, the electronic key 2 (received signal strength notification unit 22) has all the information of RSSIkey1 to RSSIkeyn. A UHF radio wave including the first received signal strength information RSSIkeym (m is 1 to n) is transmitted.

The collation ECU 4 (calculation unit 41), based on the first reception signal strength information RSSIkeym and the reception time thereof, and the second reception signal strengths RSSIcar1 to RSSIcarn and the reception time thereof, changes with time of the first reception signal strength RSSI1 and the second The time change of the received signal strength RSSI2 is calculated. Then, the verification ECU 4 (communication correctness determination unit 42) determines the vehicle 1 and the electronic key 2 based on the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 calculated by the calculation unit 41. It is determined whether the communication between the two is regular communication.

Further, when transmitting the challenge signal CH to the electronic key 2, the verification ECU 4 itself calculates the “response code” by using the “challenge code” in its own encryption key. When the verification ECU 4 receives the response signal RE from the electronic key 2, the verification ECU 4 performs response verification for confirming the correctness of the “response code” and ID code verification for confirming the correctness of the “ID code” of the electronic key 2. When the verification ECU 4 confirms that both the response verification and the ID code verification are established, the verification ECU 4 processes the vehicle outside ID verification as being established in principle, and permits or executes the door lock/unlock by the door lock device 6. With the above, the outside vehicle ID verification is completed.

Next, when it is detected that the driver gets in the vehicle, the verification ECU 4 starts transmitting the wake signal S1 by the LF radio wave toward the inside of the vehicle through the LF transmission unit 10. Thereby, communication between the vehicle 1 and the electronic key 2 in the vehicle is executed. Then, when it is confirmed that the in-vehicle ID verification is established by the same procedure as the vehicle-outside ID verification, the verification ECU 4 permits the engine ECU 7 to change the vehicle power source by operating the engine switch 9 and start the engine 8.

By the way, as shown in FIG. 4, the LF radio wave area that normally reaches the LF radio wave is set around the vehicle, but it is illegally extended by the repeater so that the LF radio wave reaches farther than the original LF radio wave area. The specified LF radio wave area may be set. Therefore, for example, even if the user puts the electronic key 2 at home far away from the vehicle 1, the LF radio wave from the vehicle 1 reaches the electronic key 2 by illegally extending the LF radio wave area. There is a risk. As a result, ID verification via wireless communication between the vehicle 1 and the electronic key 2 may be illegally started.

In this respect, as shown in FIG. 1, the communication correctness determination unit 42 of the verification ECU 4 determines, based on the time change of the first reception signal strength RSSI1 and the second reception signal strength RSSI2 calculated by the calculation unit 41, It is determined whether there is an illegal extension of the LF radio wave.

As shown in FIG. 5A, when the user enters the LF radio wave area while holding the electronic key 2, normally, the time of the first reception signal strength RSSI1 indicated by the solid line with respect to the passage of time. The change and the time change of the second received signal strength RSSI2 indicated by the broken line should also change. Since both the first received signal strength RSSI1 and the second received signal strength RSSI2 are UHF radio waves of the same frequency, even if the positional relationship between the vehicle 1 and the electronic key 2 and the propagation environment change, the first received signal strength The received signal strengths of the strength RSSI1 and the second received signal strength RSSI2 exhibit similar behavior. As an example, the first received signal strength RSSI1 and the second received signal strength RSSI2 increase or decrease as the distance between the vehicle 1 and the electronic key 2 increases or decreases.

On the other hand, as shown in FIG. 5B, when the electronic key 2 is stationary by the user placing the electronic key 2 in a storage place or the like, the first received signal strength RSSI 1 changes with time and 2 The time change of the received signal strength RSSI2 is constant regardless of the passage of time. When the electronic key 2 is stationary, the positional relationship between the vehicle 1 and the electronic key 2 and the propagation environment do not change, so the first received signal strength RSSI1 and the second received signal strength RSSI2 do not change.

Therefore, as shown in FIG. 2, the verification ECU 4 of the vehicle 1 repeats the bidirectional communication of the challenge signal CH and the response signal RE a plurality of times, and then changes the first received signal strength RSSI1 with time and the second received signal strength. It is determined whether the time change of RSSI2 has changed (step S50).

When the first reception signal strength RSSI1 and the second reception signal strength RSSI2 have changed (YES in step S50), the verification ECU 4 determines that the communication between the vehicle 1 and the electronic key 2 is regular communication ( Step S60). Then, the verification ECU 4 permits or executes unlocking of the door when the communication between the vehicle 1 and the electronic key 2 is normal communication (step S70). For example, the verification ECU 4 sets the first reception signal strength RSSI1 and the first reception signal strength RSSI1 and the first reception signal strength RSSI1 during the past fixed time (for example, after the electronic key 2 first receives the challenge signal CH until the vehicle 1 receives the response signal RE). 2 It is determined whether or not the received signal strength RSSI2 has changed. The verification ECU 4 determines that the first reception signal strength RSSI1 and the second reception signal strength RSSI2 are suddenly increased, and the electronic key 2 is considered to have entered the LF radio wave area. It is determined whether the second received signal strength RSSI2 has changed. When the first received signal strength RSSI1 and the second received signal strength RSSI2 do not change after the first received signal strength RSSI1 and the second received signal strength RSSI2 have changed, the user holds the electronic key 2. This is because it is considered stationary. For example, when the user holds the electronic key 2 and enters the LF radio wave area and then stops for a certain period of time, the first received signal strength RSSI1 and the second received signal strength RSSI2 are set while the electronic key 2 is stationary. Changes cannot be measured. However, the change in the first received signal strength RSSI1 and the second received signal strength RSSI2 is measured from the time the user holds the electronic key 2 into the LF radio wave area until the user stops.

On the other hand, when the first received signal strength RSSI1 and the second received signal strength RSSI2 have not changed (NO in step S50), the verification ECU 4 detects fraudulently extending the LF radio wave (step S80). ). That is, if the first reception signal strength RSSI1 and the second reception signal strength RSSI2 do not change at all from the time the electronic key 2 enters the LF radio wave area until the door is unlocked, the LF radio wave transmitted from the vehicle 1 It is considered that the LF radio wave reaches the stationary electronic key 2 because the mobile phone has been extended via the repeater.

According to the configuration of this embodiment, the effects described below can be obtained.
(1) It is determined by bidirectional communication of UHF radio waves between the verification ECU 4 of the vehicle 1 and the electronic key 2 whether or not the LF communication performed between the vehicle 1 and the electronic key 2 is regular communication. You can That is, if the user is carrying the electronic key 2, the positional relationship (distance) between the vehicle 1 and the electronic key 2 changes with the movement of the user, and the first received signal strength RSSI 1 changes with time. And the time variation of the second received signal strength RSSI2 should change. For example, a user who is trying to unlock the door is expected to approach the vehicle 1 over time. Therefore, if the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 do not change at all within the LF radio wave area, it is considered that the LF radio wave area has been illegally extended. In this way, it is possible to distinguish whether the LF communication is an unauthorized communication using a repeater based on the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2. In the case of illegal communication, unlocking of the door and starting of the engine are not permitted, so that it is possible to ensure security against illegal use and theft of the vehicle 1.

(2) It is possible that the user enters the LF radio wave area and then stops for a certain period of time depending on various situations such as being called off or making a phone call. In such a case, the electronic key 2 may be stationary, so that the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 do not change in the LF radio wave area for a long time. It is also possible. In this regard, in the present embodiment, if the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 do not change even after entering the LF radio wave area, the vehicle is It is determined that the communication between 1 and the electronic key 2 is regular communication. As a result, it is possible to prevent the unauthorized use of the electronic key 2 from being mistakenly determined when the authorized user operates the electronic key 2. Therefore, while ensuring the security of the vehicle 1, it is possible to more reliably determine that the electronic key 2 has been operated by the authorized user.

(3) Since the illegal extension of the LF radio wave can be detected by using the bidirectional communication of the UHF radio wave, it is not necessary to separately provide a sensor or the like for detecting the illegal extension.
The present embodiment may be modified as follows. The following other embodiments can be combined with each other within a technically consistent range.

In the present embodiment, in step S50 of FIG. 2, if the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 have changed even once after entering the LF radio wave area, the vehicle 1 Although it is determined that the communication between the electronic key 2 and the electronic key 2 is regular communication, the present invention is not limited to this. For example, when the temporal change of the first received signal strength RSSI1 and the temporal change of the second received signal strength RSSI2 do not change temporarily, it may be determined that the act is fraudulent. By doing so, it is possible to determine that all communication is illegal if it can be considered as illegal communication.

-In this embodiment, the frequency used for two-way communication is not limited to UHF, but may be LF or another frequency such as HF (High Frequency). Further, the frequency used for the start signal is not limited to LF, and may be UHF or another frequency such as HF.

In the present embodiment, the electronic key system 3 is a key operation free system, but may be an immobilizer system, for example.
The communication fraud prevention system is not limited to the communication for ID verification outside the vehicle, but may be used for communication for ID verification inside the vehicle.

The determination as to whether the communication is correct or not is not limited to being performed on the vehicle 1 side, but may be performed on the electronic key 2 side. In this case, the result of the communication right/wrong determination made on the electronic key 2 side is transmitted to the vehicle 1, and the vehicle 1 permits the locking/unlocking of the door based on the determination result. Further, the determination as to whether or not the communication is correct may be made on both the vehicle 1 side and the electronic key 2 side.

The electronic key 2 can be changed to another terminal such as a high-performance mobile phone. That is, a terminal capable of wireless communication may be provided instead of the electronic key 2.
The communication partner is not limited to the vehicle 1 and can be changed to other devices and devices.

DESCRIPTION OF SYMBOLS 1... Vehicle, 2... Electronic key (1st communication part), 3... Electronic key system, 4... Collation ECU (2nd communication part), 5... Body ECU, 6... Door lock device, 7... Engine ECU, 8... Engine, 9... Engine switch, 10... LF transmitting section, 11... UHF transmitting/receiving section, 20... Key control section, 21... Received signal strength calculation section, 22... Received signal strength notifying section, 30... LF receiving section, 31 UHF transmitter/receiver, 40... Received signal strength calculator, 41... Calculator, 42... Communication correctness determination unit, L... Communication line, S1... Wake signal, S2... Ac signal, S3... Vehicle ID signal, S4... Ac signal , CH, CH1 to CHn... Challenge signal, RE, RE1 to REn... Response signal, RSSI1... First received signal strength, RSSI2... Second received signal strength, RSSIkey1 to RSSIkeyn... First received signal strength, RSSIcar1 to RSSIcarn. 2 received signal strength, RSSIkeym... 1st received signal strength information.

Claims (2)

At least one of a first communication unit and a second communication unit that perform wireless communication with each other is movable, and the first communication unit to the second communication unit or the second communication unit to the second communication unit. Wireless communication correct/incorrect for determining whether bidirectional communication in which signals are exchanged a plurality of times between the first communication unit and the second communication unit is triggered by a start signal transmitted to the first communication unit A judgment system,
The first communication unit,
A first reception signal strength calculation unit that calculates a first reception signal strength that is a reception signal strength of a radio wave from the second communication unit, and the first reception signal strength calculation unit calculates the first reception signal strength calculation unit. The information of the received signal strength of 1 is transmitted to the second communication unit,
The second communication unit,
A second received signal strength calculation unit that calculates a second received signal strength that is the received signal strength of the radio wave transmitted from the first communication unit;
Based on the first received signal strength obtained by receiving the information on the first received signal strength, the time change of the first received signal strength, and the second received signal strength calculator And a calculation unit that calculates a time change of the second received signal strength,
The first received signal strength and the second received signal strength change during the two-way communication based on the time change of the first received signal strength and the time change of the second received signal strength. A wireless communication correctness determination system comprising: a determination unit that determines that the start signal is due to unauthorized communication when it is determined that there is no communication. The wireless communication correctness determination system according to claim 1,
The determination unit, during the bidirectional communication performed between the first communication unit and the second communication unit,
When the time change of the first received signal strength and the time change of the second received signal strength change even once, it is determined that the start signal is regular communication,
A wireless communication correctness determination system that determines that the start signal is due to unauthorized communication when the time change of the first received signal strength and the time change of the second received signal strength do not change at all.

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