WO2018066337A1

WO2018066337A1 - Wireless communication normality determination system

Info

Publication number: WO2018066337A1
Application number: PCT/JP2017/033303
Authority: WO
Inventors: 一輝内木; 惠森; 花木　秀信; 明暁岩下; 佳之大屋
Original assignee: 株式会社東海理化電機製作所
Priority date: 2016-10-04
Filing date: 2017-09-14
Publication date: 2018-04-12
Also published as: JP2018059308A; JP6702840B2

Abstract

Two-way communication between a first communication unit (2) and a second communication unit (4) is performed with a start signal transmitted from the second communication unit (or first communication unit) as a trigger. The first communication unit calculates a first received signal strength of a radio wave transmitted from the second communication unit, and the second communication unit calculates a second received signal strength of a radio wave transmitted from the first communication unit. A determination unit (42) of the second communication unit (4) determines whether the communication including start communication between the first communication unit and the second communication unit is normal communication or not on the basis of the temporal change of the first received signal strength and the temporal change of the second received signal strength.

Description

Wireless communication pass / fail judgment system

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

2. Description of the Related Art Conventionally, an electronic key system that performs ID verification by wireless communication between an electronic key (mobile device) and a vehicle is known. 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 ID verification is established outside the vehicle, door locking / unlocking is permitted, and when ID verification is established inside the vehicle, engine start is permitted.

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

For this reason, as shown in Patent Document 2, there is one that determines whether or not the communication is regular communication based on the RSSI (reception signal strength) of the radio wave used for communication between the vehicle and the electronic key. The method for determining whether or not 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 they do not match, there is one that determines that this bidirectional communication is not regular communication. Thereby, even if it is a case where the radio wave of bidirectional communication is relayed, it can be judged whether bidirectional communication is regular communication by using RSSI of the radio wave of 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 a start signal is transmitted from the vehicle to the electronic key. This start signal may also be sent to an electronic key located far away from the vehicle through a plurality of relays between the vehicle and the electronic key. In this regard, the method for determining whether or not the communication is regular communication based on the degree of coincidence of the RSSI time change of the radio wave of bidirectional communication can determine whether or not the bidirectional communication is regular communication, but bidirectional communication is started. It is difficult to determine whether or not the start signal before being sent is regular communication.

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

One aspect of the wireless communication correctness determination system includes a first communication unit and a second communication unit that perform wireless communication with each other, and at least one of the first and second communication units is movable, The first communication unit and the second communication unit triggered by a start signal transmitted from the first communication unit to the second communication unit or from the second communication unit to the first communication unit A wireless communication correctness determination system that determines the correctness of bidirectional communication in which a plurality of signals are exchanged with the first communication unit, wherein the first communication unit transmits radio waves transmitted from the second communication unit. A first received signal strength calculating unit that calculates a first received signal strength that is a received signal strength, and information about the first received signal strength calculated by the first received signal strength calculating unit 2 to the communication unit, and the second communication unit A second received signal strength calculating unit that calculates a second received signal strength that is a received signal strength of a radio wave transmitted from the communication unit, and the information obtained by receiving the information on the first received signal strength. A calculating unit that calculates a time change of the first received signal strength based on a first received signal strength and a time change of the second received signal strength calculated by the second received signal strength calculating unit; The first received signal strength and the second received signal strength change during the bidirectional communication based on the time change of the first received signal strength and the time change of the second received signal strength. A determination unit that determines that the start signal is due to unauthorized communication when it is determined that the start signal is not.

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 reception signal strength and the time change of the second reception signal strength calculated by the calculation unit. It is possible to determine that at least one of the movable units is in a stationary state and determine whether the start signal is unauthorized communication based on the determination result.

For example, when the first communication unit and the second communication unit are close to each other, the first reception signal strength and the second reception signal strength increase as the proximity increases. When the two communication units are separated from each other, the first received signal strength and the second received signal strength become smaller as they are separated from each other. Therefore, the temporal change of the first received signal strength and the second received signal The intensity change over time should change. When the time change of the first received signal strength and the time change of the second received signal strength are not changed, 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 can be received to 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 remain stationary even though the communication unit needs to be close to each other, it is considered that the start signal is illegally extended by a repeater or the like. . For this reason, the start signal is illegally determined by determining the stationary state of the first communication unit and the second communication unit using bidirectional communication between the first communication unit and the second communication unit. It can be determined that unauthorized communication such as extension is being performed.

In the wireless communication correct / incorrect determination system, the determination unit includes a temporal change in the first received signal strength during bidirectional communication performed between the first communication unit and the second communication unit, and When the time change of the second received signal strength is even once, it is determined that the start signal is due to regular communication, and the time change of the first received signal strength and the time of the second received signal strength are determined. When there is no change, it is preferable to determine that the start signal is due to unauthorized communication.

According to this configuration, for example, when the first communication unit or the second communication unit is stationary after the first communication unit or the second communication unit receives the start signal, the first received signal strength changes with time. Even when the first communication unit or the second communication unit receives the start signal, the first received signal even if the time change of the second received signal strength and the time change of the second received signal intensity disappear for a certain period of time. If there is a time change in strength and a time change in second received signal strength, it is determined that the start signal is due to regular communication. For this reason, even if the first communication unit or the second communication unit stops after receiving the start signal, it can be more correctly determined that the start signal is due to regular communication.

In the wireless communication correctness determination system, the first communication unit repeats transmission / reception through the bidirectional communication a plurality of times between the first communication unit and the second communication unit, and then 1 received signal strength information is transmitted to the second communication unit, and the determination unit of the second communication unit receives the first reception after the transmission / reception through the bidirectional communication is repeated a plurality of times. It is preferable to determine whether a time change in signal strength and a time change in the second received signal strength have occurred.

According to this configuration, after a plurality of transmissions / receptions, the determination unit performs regular communication in order to determine whether a time change in the first received signal strength and a time change in the second received signal strength have occurred. Can be determined with high accuracy and determination is not performed for each transmission / reception, so that the determination process can be simplified.

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

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

Hereinafter, an embodiment of a wireless communication correctness determination system will be described.
As shown in FIG. 1, there is an electronic key system 3 that performs ID verification by performing wireless communication between a vehicle 1 and an electronic key 2. An electronic key ID unique to the electronic key 2 is written and stored in the electronic key 2. The electronic key system 3 of this 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 (start 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 the driving of in-vehicle electrical components such as the door lock device 6, and an engine ECU 7 that controls the 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 through a communication line L in the vehicle. As the communication line L, CAN (Controller | Area | Network) is used, for example. 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 transmission unit 10 that transmits radio waves in the LF (Low Frequency) band inside and outside the vehicle, and a UHF transmission / reception unit 11 that transmits and receives radio waves in the UHF (Ultra High Frequency) band inside and outside the vehicle. An LF transmitter 10 and a UHF transmitter / receiver 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 using a UHF band radio wave (UHF radio wave) as an ID reply request to the electronic key 2. In this example, 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 and receives UHF radio waves. An LF receiver 30 and a UHF transmitter / receiver 31 are connected to the key controller 20. In the key control unit 20, an “ID code” is written and stored in a memory (not shown) as an electronic key ID. The UHF band radio wave transmitted from the UHF transmission / reception unit 11 of the vehicle 1 and the UHF band radio wave transmitted from the UHF transmission / reception unit 31 of the electronic key 2 are radio waves of the same frequency.

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

The verification ECU 4 executes in-vehicle ID verification when the electronic key 2 enters the in-vehicle communication area of the UHF transmission / reception unit 11 after the external 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 by the operation of the engine switch 9 and the start of the engine 8.

Also, the electronic key system 3 (wireless communication correctness determination system) has a function of suppressing unauthorized communication using a repeater by a third party, for example. A fraudulent act using a repeater means that when a user who owns the electronic key 2 is far away from the vehicle 1, a third party who attempts to steal the vehicle relays radio waves using the repeater. Thus, this 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 received signal strength calculating unit 21 that calculates a received signal strength (RSSI) of the received radio wave when a radio wave in the UHF band from the verification ECU 4 is received. When the reception signal strength calculation unit 21 receives a radio wave by the UHF transmission / reception unit 31, the reception signal strength calculation unit 21 calculates the first reception signal strength RSSI1 by detecting the amplitude of the received radio wave. The received signal strength calculation unit 21 calculates the first received signal strength RSSI1 of the UHF radio wave in association with the reception time each time a UHF radio wave is received from the vehicle 1.

The key control unit 20 of the electronic key 2 also receives the first received signal strength RSSI1 calculated by the received signal strength calculating unit 21 and the received signal strength that notifies the vehicle 1 of the reception time associated with the first received signal strength RSSI1. A notification unit 22 is provided. When the electronic key 2 transmits various UHF radio waves in response to an inquiry from the vehicle 1, the reception signal strength notification unit 22 includes the first reception signal strength RSSI 1 in addition to the “ID code” and the “response code”. Send data including information 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 received signal intensity calculating unit 40 calculates a second received signal intensity RSSI 2 that is the received signal intensity of the UHF radio wave. The received signal strength calculation unit 40 calculates the second received signal strength RSSI2 that is the received signal strength of the UHF radio wave in association with the reception time each time the UHF radio wave is received from the electronic key 2.

Based on the first received signal strength RSSI1 calculated by the received signal strength calculating unit 21 and its reception time, and the second received signal strength RSSI2 calculated by the received signal strength calculating unit 40 and the received time, A time change (trajectory) of the first received signal strength RSSI1 and a time change (trajectory) of the second received signal strength RSSI2 are calculated.

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, the communication correctness determination unit 42 determines that the communication between the vehicle 1 and the electronic key 2 is normal. It is determined 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.
As shown in FIG. 2, when the vehicle is parked, a wake signal S <b> 1 by an LF band radio wave (LF radio wave) is intermittently transmitted from the LF transmission unit 10 to the outside of the vehicle. In the present embodiment, the wake signal S1 is an example of a start signal. When the electronic key 2 receives the wake signal S1, communication between the vehicle 1 and the electronic key 2 outside the vehicle is established. When communication outside the vehicle is established, an ACK signal S2 based on a UHF radio wave (UHF radio wave) is returned from the electronic key 2.

When the verification ECU 4 receives the ACK signal S2 after transmitting the wake signal S1, the verification ECU 4 transmits a vehicle ID signal S3 using UHF radio waves. The vehicle ID signal S3 is a signal including “vehicle ID” that is a unique ID of the vehicle 1. When receiving the vehicle ID signal S3, the electronic key 2 performs vehicle ID verification. When the electronic key 2 confirms that the vehicle ID verification is established, the electronic key 2 returns the ACK signal S4 by the UHF radio wave again.

When the verification ECU 4 receives the ACK signal S4 after transmitting the vehicle ID signal S3, the verification 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 receiving the first challenge signal CH1, the electronic key 2 first checks the key number. Next, when it is confirmed that the key number verification is established, the electronic key 2 calculates a “response code” from the “challenge code” using its own encryption key. Further, 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 CH1. The first response signal RE1 (RE) by the UHF radio wave not including the first received signal strength RSSIkey1 is transmitted. The response signal RE1 includes a “response code”. When the verification ECU 4 receives the first response signal RE1, the verification ECU 4 calculates the second received signal strength RSSIcar1 when the first response signal RE1 is received in association with the reception time of the first response signal RE1, A second challenge signal CH2 by the 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 1 Response signal RE2 of the 2nd time by the UHF electric wave which does not contain received signal strength RSSIkey2 is transmitted. When the verification ECU 4 receives the second response signal RE2, the verification ECU 4 calculates the second received signal strength RSSIcar2 when the second response signal RE2 is received in association with the reception time of the second response signal RE2, The third and subsequent challenge signals (hereinafter, not shown) by UHF radio waves are transmitted.

When the electronic key 2 receives the nth challenge signal CHn, the electronic key 2 calculates the first received signal strength RSSIkeyn of the nth challenge signal CHn in association with the reception time of the nth challenge signal CHn, The first response signal REn by the UHF radio wave not including one received signal strength RSSIkeyn is transmitted. When the verification ECU 4 receives the nth response signal REn, the verification ECU 4 calculates the second received signal strength RSSIcarn when the nth response signal REn is received in association with the reception time of the nth response signal REn.

Then, after bidirectional communication of the challenge signal CH and the response signal RE is repeated n times and the nth response signal REn 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 verification ECU 4 (calculation unit 41) determines the first received signal strengths RSSIkey1 to RSSIkeyn (first received signal strength information RSSIkeym) and the reception time thereof, and the second received signal strengths RSSIcar1 to RSSIcarn and the reception time thereof. The time change of the received signal strength RSSI1 and the time change of the second received signal strength RSSI2 are 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 reception signal strength RSSI1 and the time change of the second reception signal strength RSSI2 calculated by the calculation unit 41. It is determined whether the communication between the two is regular communication.

In addition, when the verification ECU 4 transmits the challenge signal CH to the electronic key 2, the verification ECU 4 itself calculates the “response code” from the “challenge code” using 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 whether the “response code” is correct and ID code verification for confirming whether the “ID code” of the electronic key 2 is correct. When the verification ECU 4 confirms that both the response verification and the ID code verification are established, the verification ECU 4 processes that the ID verification outside the vehicle is established in principle, and permits or executes the door lock locking / unlocking by the door lock device 6. The vehicle ID verification is thus completed.

Next, when it is detected that the driver has boarded the vehicle, the verification ECU 4 starts to transmit the wake signal S <b> 1 by the LF radio wave toward 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, the verification ECU 4 permits the engine ECU 7 to change the vehicle power supply and start the engine 8 by operating the engine switch 9 when it is confirmed that the vehicle ID verification is established by the same procedure as the vehicle ID verification.

By the way, as shown in FIG. 4, an LF radio wave area where LF radio waves usually reach around the vehicle is set, but the LF radio wave is illegally extended by a repeater so that the LF radio waves reach farther than the original LF radio wave area. There is a risk of setting the LF radio wave area. For this reason, for example, even if the user places the electronic key 2 at home far away from the vehicle 1, the LF radio wave area from the vehicle 1 reaches the electronic key 2 by improperly extending the LF radio wave area. There is a fear. Thereby, ID collation through wireless communication between the vehicle 1 and the electronic key 2 may be illegally started.

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

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

On the other hand, as shown in FIG. 5B, when the electronic key 2 is stationary due to the user placing the electronic key 2 in a storage location or the like, the first received signal strength RSSI1 changes with time. 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 two-way communication of the challenge signal CH and the response signal RE a plurality of times, and then changes with time in the first received signal strength RSSI1 and the second received signal strength. It is determined whether there is a change in RSSI2 over time (step S50).

When the first received signal strength RSSI1 and the second received signal strength RSSI2 are 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). And collation ECU4 permits or performs unlocking | release of a door, when communication between the vehicle 1 and the electronic key 2 is regular communication (step S70). For example, the collation ECU 4 determines the first received signal strength RSSI1 and the first received signal strength RSSI1 during the past fixed time (for example, from when the electronic key 2 first receives the challenge signal CH to when the vehicle 1 receives the response signal RE). 2 Determine whether the received signal strength RSSI2 has changed. The verification ECU 4 determines that the first received signal strength RSSI1 and the second received signal strength RSSI1 and the second received signal strength RSSI2 suddenly increase from the time when 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 change, the user holds the electronic key 2 This is because it is considered stationary. For example, the first received signal strength RSSI1 and the second received signal strength RSSI2 are maintained while the electronic key 2 is stationary by, for example, stopping for a certain time after entering the LF radio wave area with the user holding the electronic key 2. 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 when the user enters the LF radio wave area while holding the electronic key 2 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 an illegal act in which the LF radio wave is illegally extended (step S80). ). That is, when the first received signal strength RSSI1 and the second received signal strength RSSI2 do not change at all after the electronic key 2 enters the LF radio wave area and before the door unlocking operation is performed, the LF radio wave transmitted from the vehicle 1 Is extended through the repeater, it is considered that the LF radio wave has reached the electronic key 2 in a stationary state.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) It is determined whether or not the LF communication performed between the vehicle 1 and the electronic key 2 is regular communication by bidirectional communication of UHF radio waves between the verification ECU 4 of the vehicle 1 and the electronic key 2. Can do. That is, if the user is carrying the electronic key 2, the temporal change in the first received signal strength RSSI1 is equivalent to the change in the positional relationship (distance) between the vehicle 1 and the electronic key 2 according to the user's movement. And a time change of the second received signal strength RSSI2 should occur. For example, if it is a user who is going to perform unlocking operation of a door, approaching the vehicle 1 with progress of time is assumed. For this reason, if the time change of the 1st received signal strength RSSI1 and the time change of the 2nd 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. Thus, based on the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2, it is possible to distinguish whether the LF communication is unauthorized communication using a repeater. In the case of unauthorized communication, unlocking of the door and starting of the engine are not permitted, so that security against unauthorized use and theft of the vehicle 1 can be ensured.

(2) After entering the LF radio wave area, the user may be stopped for a certain period of time depending on various situations such as being called or telephoned. In such a case, since the electronic key 2 may be stationary, 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 over a long period of time. It is also possible. In this regard, in the present embodiment, when the time change does not occur after the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 occur even once after entering the LF radio wave area. Then, it is determined that the communication between the vehicle 1 and the electronic key 2 is regular communication. Thereby, when a legitimate user operates electronic key 2, it is controlled that it is judged that it is improper use accidentally. For this reason, it can determine more reliably that the electronic key 2 was operated by the authorized user, ensuring the security of the vehicle 1.

(3) Since it is possible to detect an unauthorized extension of the LF radio wave using bidirectional communication of UHF radio waves, it is not necessary to separately provide a sensor or the like for detecting the illegal extension.
In addition, you may change this embodiment 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 occur even once after entering the LF radio wave area, the vehicle 1 However, the present invention is not limited to this. For example, when the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 do not occur temporarily, it may be determined that it is an illegal act. In this way, it can be determined that all communication is illegal if it can be considered as illegal communication.

In the present embodiment, the frequency used for bidirectional communication is not limited to UHF, but may be LF, or other frequency such as HF (High Frequency). Further, the frequency used for the start signal is not limited to LF, and may be UHF or other frequencies 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 establishment prevention system is not limited to being applied to communication outside the vehicle ID collation, but may be used for communication within the vehicle ID verification.

The determination of whether communication is correct or not is not limited to being performed by the vehicle 1, but may be performed by the electronic key 2. In this case, the determination result of the communication correctness performed with the electronic key 2 is transmitted to the vehicle 1, and the vehicle 1 permits the door to be locked and unlocked based on the determination result. Further, whether the communication is correct or not may be determined by both the vehicle 1 and the electronic key 2.

The electronic key 2 can be changed to another terminal such as a high function 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 such as a device that controls the locking and unlocking of the doors of the building.

Claims

A first communication unit and a second communication unit that perform wireless communication with each other, wherein at least one of the first communication unit and the second communication unit is movable; Sending and receiving signals multiple times between the first communication unit and the second communication unit triggered by a start signal transmitted to the communication unit or from the second communication unit to the first communication unit A wireless communication correct / incorrect determination system for determining whether or not bidirectional communication is performed,
The first communication unit is
A first received signal strength calculating unit that calculates a first received signal strength that is a received signal strength of a radio wave transmitted from the second communication unit, and is calculated by the first received signal strength calculating unit; Transmitting the first received signal strength information to the second communication unit;
The second communication unit is
A second received signal strength calculating unit that calculates a second received signal strength that is a received signal strength of a 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 calculation unit are calculated. Calculating a time change of the second received signal strength;
Based on the time change of the first received signal strength and the time change of the second received signal strength, the first received signal strength and the second received signal strength change during the bidirectional communication. And a determination unit that determines that the start signal is due to unauthorized communication when it is determined that the start signal is not.
In the wireless communication correctness determination system according to claim 1,
During the bidirectional communication performed between the first communication unit and the second communication unit, the determination unit,
When the time change of the first received signal strength and the time change of the second received signal strength are even once, determine that the start signal is due to regular communication,
A wireless communication correctness determination system that determines that the start signal is due to unauthorized communication when there is no time change of the first received signal strength and no time change of the second received signal strength.
In the wireless communication correctness determination system according to claim 1 or 2,
The first communication unit repeats transmission / reception through the bidirectional communication between the first communication unit and the second communication unit a plurality of times, and then transmits the first received signal strength information to the first communication unit. To the second communication unit,
The determination unit of the second communication unit causes a time change of the first received signal strength and a time change of the second received signal strength after transmission / reception through the bidirectional communication is repeated a plurality of times. Wireless communication correctness determination system for determining whether or not