WO2017131114A1 - System for determining correctness of wireless communication - Google Patents

Abstract

A system in which a vehicle (1) and an electronic key (2) communicate by UHF radio waves (24, 28) of the same frequency band, wherein the electronic key (2) calculates the received signal strength of the radio waves (24) from the vehicle (1) and transmits received signal strength information (30) indicating the received signal strength to the vehicle (1). The vehicle (1) calculates the difference between the received signal strength information (30) received from the electronic key (2) and the received signal strength of the radio waves (28) in which the received signal strength information (30) is carried, and confirms whether or not this difference is within a reference range, thereby determining the communication correctness of smart communication.

Description

Wireless communication pass / fail judgment system

The present invention relates to a wireless communication correctness determination system in which a communication terminal and a communication master perform wireless communication.

2. Description of the Related Art Conventionally, many vehicles are equipped with an electronic key system (see Patent Document 1 or the like) that collates an ID code of an electronic key transmitted wirelessly from an electronic key (also referred to as a portable device). In this type of electronic key system, when an electronic key receives a request transmitted from a vehicle, the electronic key automatically returns an ID code to the vehicle in response to the request, and performs an ID verification. There is. In the key operation free system, when ID verification is established outside the vehicle, door locking / unlocking is permitted or executed, and when ID verification is established inside the vehicle, engine start operation is permitted.

In such an electronic key system, it is desired to prevent fraud using a repeater (see Patent Document 2 and Patent Document 3). For example, when the electronic key is located at a location far from the vehicle, a third party relays the electronic key to the vehicle using a plurality of relays to establish communication.

In Patent Document 2, both the RSSI (reception signal strength) of the LF signal from the vehicle to the portable device and the RSSI of the RF signal from the portable device to the vehicle are detected, and when one of the RSSIs is extremely small, the repeater It is determined that this is an illegal act of use, and the door is not allowed to be locked or unlocked or the engine is started.

In Patent Document 3, the vehicle transmits a transmission signal with radio waves having different intensities, and the electronic key calculates the received signal strength of the received radio waves. Then, based on the calculated received signal strength, it is determined whether or not the communication is normal.

JP 2005-262915 A JP 2012-60482 A JP 2011-229061 A

By the way, conventionally, when performing communication with the LF signal from the vehicle to the electronic key and communication with the RF signal from the electronic key to the vehicle, either of them may be null in the antenna direction. Since it is erroneously determined that there has been a fraudulent act of using the repeater, the door cannot be locked / unlocked and the engine cannot be started normally. For this reason, it is necessary to consider the relative difference between the LF signal and the RF signal. As a result, the criteria for determining whether or not to use the repeater may be relaxed, and the repeater use incorrect action may not be detected.

An object of the present invention is to provide a wireless communication correct / incorrect determination system that can prevent the occurrence of unauthorized wireless communication using a repeater.
A wireless communication correctness determination system according to one aspect of the present invention includes a first communication unit including a first transmission execution unit, and a second communication unit including a second transmission execution unit, and the first transmission execution unit and the first transmission unit. A wireless communication correctness determination system capable of performing two-way radio communication in the same frequency band with each other, wherein the first communication unit is a reception signal strength of radio waves from the second communication unit. 1st received signal strength calculation means which calculates 1 received signal strength is transmitted, the information of the 1st received signal strength is transmitted via the 1st transmission execution means, and the 2nd communications department is the 1st communications department A second received signal strength calculating means for calculating a second received signal strength that is a received signal strength of a radio wave from: a calculating means for calculating a determination value based on the first received signal strength and the second received signal strength; The comparison result between the judgment value and the reference range Based on communications with the first communication unit and a communication propriety determining means for determining whether or not normal communication.

According to this configuration, since bidirectional radio communication between the second communication unit and the first communication unit is performed in the same frequency band, the antenna directivity and the distance between the second communication unit and the first communication unit are not affected. The determination value based on the first received signal strength (radio wave strength) and the second received signal strength (radio wave strength) falls within the reference range. On the other hand, when communication is performed between the second communication unit and the first communication unit via the repeater, the determination value based on the first received signal strength and the second received signal strength is not within the reference range. . Therefore, it is possible to determine whether or not the normal communication is performed by comparing the determination value based on the first received signal strength and the second received signal strength with the reference range.

The calculating means may calculate a difference between the first received signal strength and the second received signal strength as the determination value.
According to this configuration, since the determination value is the difference between the first received signal strength and the second received signal strength, it is possible to quickly determine whether the communication is regular communication with a simple calculation.

The calculating means may calculate a degree of coincidence between a time change of the first received signal strength and a time change of the second received signal strength as the determination value.
According to this configuration, even if the positional relationship between the second communication unit and the first communication unit or the radio wave propagation environment changes, it is possible to detect a repeater use fraud.

A plurality of antennas connected to at least one of the first communication unit and the second communication unit and used for bidirectional communication between the first communication unit and the second communication unit; A switching unit that switches an antenna used for bidirectional communication between the plurality of antennas may be included.

According to this configuration, the switching unit switches between the plurality of antennas during the bidirectional communication between the first communication unit and the second communication unit, so that the first communication unit and the second communication unit are switched. Change the propagation path between. In this regard, when communication is performed between the first communication unit and the second communication unit without using a repeater, the time change of the first received signal strength and the time change of the second received signal strength are changed. Match. On the other hand, when communication is performed between the first communication unit and the second communication unit via the repeater, the time change of the first received signal strength does not match the time change of the second received signal strength. Thereby, it can be determined whether it is regular communication based on whether the time change of the 1st received signal strength and the time change of the 2nd received signal strength correspond.

An antenna connected to at least one of the first communication unit and the second communication unit and used for bidirectional communication between the first communication unit and the second communication unit, both during bidirectional communication And a switching unit that switches the directivity of the antenna used for direct communication.

According to this configuration, the switching unit switches between the first communication unit and the second communication unit by switching the directivity of the antenna during bidirectional communication between the first communication unit and the second communication unit. The propagation path of is changed. Thereby, it can be determined whether it is regular communication based on whether the time change of the 1st received signal strength and the time change of the 2nd received signal strength correspond.

The communication correctness determination unit may determine that the communication is not normal when there are a plurality of times when the comparison result between the determination value and the reference range indicates that the communication is not normal.
According to this configuration, if there is a repeater use fraud, the comparison result between the determination value based on the first received signal strength and the second received signal strength and the reference range indicates that the repeater use is fraudulent. Since there are many cases where the number of times is different, it can be determined that the communication is not regular communication when the number of times differs.

The first communication unit includes a first comparison unit that compares the first received signal strength with a first threshold value for detecting a received signal strength saturation, and the first received signal strength exceeds the first threshold value. The first transmission execution means transmits a first attenuation request to the second communication unit, and the second transmission execution means determines that the transmission output is greater than the previous output based on the first attenuation request. The power is controlled so as to be attenuated, and a radio wave is transmitted to the first communication unit, and the calculation means is transmitted from the first communication unit after the transmission output is attenuated and transmitted, and the first communication unit transmits the radio wave. The determination value may be calculated on the basis of the second received signal strength of the radio wave without the attenuation request and the new first received signal strength notified by the radio wave for which the second received signal strength is calculated.

According to this configuration, if the first communication unit and the second communication unit are close to each other and the first received signal strength may exceed the first threshold value for detecting the received signal strength saturation, the first received signal strength is It may be saturated. In this case, since the first attenuation request is sent from the first communication unit to the second communication unit, the second communication unit performs power control so that the transmission output is attenuated from the previous output based on the first attenuation request. To transmit radio waves to the first communication unit. Then, the calculation means of the second communication unit attenuates the transmission output and transmits the radio wave, and then the second received signal strength of the radio wave transmitted from the first communication unit and the radio wave from which the second received signal strength is calculated. The determination value is calculated based on the new first received signal strength notified in (1). Accordingly, the communication correctness determination unit can determine whether or not the communication is normal using a determination value based on the new first received signal strength and the second received signal strength.

The second communication unit includes a second comparing unit that compares the second received signal strength with a second threshold value for detecting a received signal strength saturation, and the second received signal strength exceeds the second threshold value. The second transmission execution means transmits a second attenuation request to the first communication unit, and the first transmission execution means has a transmission output from a previous output based on the second attenuation request. The power is controlled so as to be attenuated and radio waves are transmitted to the second communication unit, and the calculation means is transmitted from the first communication unit after transmitting the second attenuation request, and the second attenuation request The determination value may be calculated based on the new second received signal strength of the radio wave that does not need to be transmitted and the first received signal strength notified by the radio wave for which the new second received signal strength is calculated. .

According to this configuration, when the first communication unit and the second communication unit are close to each other and the second received signal strength may exceed the second threshold value for detecting the received signal strength saturation, the second received signal strength is It may be saturated. In this case, since the second attenuation request is sent from the second communication unit to the first communication unit, the first communication unit performs power control so that the transmission output is attenuated from the previous output based on the second attenuation request. To transmit radio waves to the second communication unit. Then, the calculation means of the second communication unit transmits a second second received signal strength of a radio wave transmitted from the first communication unit after transmitting the second attenuation request and does not require the second attenuation request, and the new A determination value is calculated based on the first received signal strength notified by the radio wave for which the second received signal strength is calculated. Thereby, the communication correctness determination unit can determine whether or not the communication is normal using a determination value based on the first received signal strength and the new second received signal strength.

A wireless communication correctness determination system according to another aspect of the present invention includes a first communication unit including a first transmission execution unit, and a second communication unit including a second transmission execution unit, and the first transmission execution unit and the A wireless communication correctness determination system capable of executing bidirectional radio communication in the same frequency band with the second transmission execution means, wherein the first communication unit is a received signal intensity of radio waves from the second communication unit First reception signal strength calculation means for calculating a first reception signal strength is provided, information on the first reception signal strength is transmitted via the first transmission execution means, and the second communication unit is configured to transmit the first communication signal. A second received signal strength calculating means for calculating a second received signal strength which is a received signal strength of a radio wave from the unit, and a degree of coincidence between a time change of the first received signal strength and a time change of the second received signal strength Calculating means for calculating a determination value indicating Communication correct / incorrect determination means for determining whether communication with the first communication unit is normal communication based on a comparison result between the determination value and a reference range, and the first received signal strength calculation means includes: Each time a radio wave is received from the second communication unit, a first received signal strength associated with a reception time is calculated, and the first communication unit receives a first of a plurality of reception opportunities via the first transmission execution unit. Received signal strength information is transmitted collectively.

According to this configuration, since bidirectional radio communication between the second communication unit and the first communication unit is performed in the same frequency band, the antenna directivity and the distance between the second communication unit and the first communication unit are not affected. In addition, even if the positional relationship between the second communication unit and the first communication unit and the propagation environment of the radio wave change, the time change of the first received signal strength (radio wave strength) and the second received signal strength (radio wave strength) The determination value indicating the degree of coincidence with the time change is within the reference range. On the other hand, when communication is performed between the second communication unit and the first communication unit via the repeater, the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength is determined. The judgment value shown does not fall within the reference range. Therefore, it is possible to determine whether or not the normal communication is performed by comparing the determination value indicating the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength with the reference range.

Since the first communication unit collectively transmits information on the first received signal strengths of a plurality of reception opportunities, each time the first communication unit receives a radio wave from the second communication unit, a first of the received radio waves is received. Each response radio wave can be simplified when transmitting a response radio wave to the radio wave from the second communication unit as compared with the case of transmitting the received signal strength information.

When the first communication unit transmits information on the first received signal strength of the received radio wave every time it receives a radio wave from the second communication unit, the second communication unit uses the first received signal strength information. The next radio wave may not be transmitted until is received. However, this configuration does not cause this inconvenience, so that bidirectional communication can be performed smoothly.

According to one or more aspects of the present invention, it is possible to prevent unauthorized establishment of wireless communication using a repeater. Other aspects and advantages of the present invention will become apparent from the following description taken in conjunction with the drawings, which illustrate examples of the technical spirit of the present invention.

The block diagram of the communication fraud establishment prevention system of 1st Embodiment. 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. The flowchart of the right-and-left determination of the radio | wireless communication of the radio | wireless communication correctness determination system in smart communication. Explanatory drawing of the path | route in the radio | wireless communication between a vehicle and an electronic key. Explanatory drawing of the path | route in the radio | wireless communication between the vehicle and electronic key in the case of the one side relay system. The block diagram of the communication fraud establishment prevention system of 2nd Embodiment. The block diagram of the communication fraud establishment prevention system of 3rd Embodiment. The block diagram of the communication fraud establishment prevention system of 4th Embodiment. 10 is a flowchart of wireless communication correctness determination in the wireless communication correctness determination system in smart communication according to the fifth embodiment. The graph which shows the time change of the 1st received signal strength, and the time change of the 2nd received signal strength. The block diagram which shows the structure of the communication fraud establishment prevention system of 6th Embodiment. The flowchart of the right / no-go determination of the radio | wireless communication of the radio | wireless communication correctness determination system in the smart communication in 6th Embodiment. (A), (b) is explanatory drawing of the path | route in the radio | wireless communication between the vehicle and electronic key in 6th Embodiment. (A), (b) is a graph which shows the time change of the 1st received signal strength and the time change of the 2nd received signal strength in 6th Embodiment. (A)-(c) is a block diagram of the switching part in other embodiment.

(First embodiment)
A first embodiment of a communication fraud prevention system embodying the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the vehicle 1 transmits a wireless inquiry (request signal Srq) from the vehicle 1 to the electronic key 2, and performs ID verification based on a response (ID signal Sid) of the electronic key 2 to this inquiry. A key operation free system 3 is installed. The key operation free system 3 includes an entry function in which door locking / unlocking is permitted or executed when ID verification is established outside the vehicle, and a power transition operation of the vehicle 1 and the engine by the engine switch 4 in the vehicle when ID verification is established in the vehicle. There is an engine start function in which the start operation is permitted. The electronic key 2 is an example of a communication terminal and corresponds to the first communication unit, the request signal Srq corresponds to an inquiry, and the ID signal Sid corresponds to a response.

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 the locking and unlocking of the door, and an engine starter 7 that manages the operation of the engine. These are connected by an in-vehicle bus 8. The key verification device 5 is provided with a control unit of the key verification device 5 or a verification ECU (Electronic Control Unit) 9. 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 is an example of a communication master and corresponds to the second communication unit.

The verification ECU 9 transmits an LF (Low Frequency) band radio wave to the outside and the inside of the vehicle, and transmits an UHF (Ultra High Frequency) band radio wave and the UHF band to the outside and inside the vehicle. A UHF transceiver 12 is connected.

The UHF transmitter / receiver 12 transmits a request signal Srq as an ID reply request to the electronic key 2 by a radio wave in the UHF band, and attempts to establish so-called smart communication.
On the other hand, the electronic key 2 is provided with a key control unit 13 that performs overall control of the operation of the electronic key 2. An ID code that is an ID unique to the key is registered in a memory (not shown) of the key control unit 13. The key control unit 13 includes an LF receiver 14 that can receive LF band radio waves, a UHF band that can receive UHF band radio waves and that has the same frequency band as the UHF band radio waves transmitted from the key verification device 5. Is connected to a UHF transmitter / receiver 15 capable of transmitting the radio wave.

As shown in FIG. 2, when the vehicle is parked, an LF band wake signal 16 is intermittently transmitted from the LF transmitter 11, and the wake signal 16 is received by the electronic key 2 so that smart communication outside the vehicle (external communication) is performed. When established, a UHF band ACK signal 17 is returned from the electronic key 2.

When the verification ECU 9 receives the ACK signal 17 after transmitting the wake signal 16, the verification ECU 9 subsequently transmits a vehicle ID 18 in the UHF band. The vehicle ID 18 is a unique ID of the vehicle 1. When the electronic key 2 receives the vehicle ID 18, it performs vehicle ID collation. When the electronic key 2 confirms that the vehicle ID collation is established, the electronic key 2 returns the UHF band ACK signal 19 again.

When the verification ECU 9 receives the ACK signal 19 after transmitting the vehicle ID 18, the verification ECU 9 subsequently transmits a challenge 20. The challenge 20 includes a challenge code 20a and a key number 20b. The challenge 20 corresponds to the request signal Srq.

When the electronic key 2 receives the challenge 20, first, the key number is collated, and if the collation is confirmed, the challenge code 20 a is passed through the encryption key of the electronic key 2 and the response code 21 a is calculated. Then, the electronic key 2 transmits a response 21 including the response code 21a and the ID code 21b as main data. Here, the response 21 corresponds to the ID signal Sid.

When the verification ECU 9 transmits the challenge 20 to the electronic key 2, the verification ECU 9 calculates a response code through the challenge code 20a with the encryption key of the verification ECU 9. When the verification ECU 9 receives the response 21 from the electronic key 2, the response verification that confirms whether the response code 21 a received from the electronic key 2 and the response code calculated by the verification ECU 9 are correct, and the ID code 21 b received from the electronic key 2 ID code verification is performed to check whether the ID code of the electronic key 2 registered in the verification ECU 9 is correct. When the verification ECU 9 confirms that both verifications have been established, in principle, the verification ECU 9 processes smart verification (external vehicle verification) as successful, and permits or executes door locking / unlocking by the door lock device 6.

Further, when it is detected by a courtesy switch or the like that the driver has boarded, for example, transmission of the LF band wake signal 16 from the LF transmitter 11 to the inside of the vehicle is started, and smart communication ( Car communication) is executed. Then, whether or not smart verification (in-vehicle verification) is established in the vehicle is confirmed by the same procedure as that in the vehicle verification, and when the verification in the vehicle is confirmed, power supply transition operation and engine start operation by the engine starting device 7 are permitted. .

In the case of the present embodiment, as shown in FIG. 1, the key operation free system 3 is provided with a communication fraud establishment prevention system 23 for preventing the smart communication fraud establishment using the repeater 22 shown in FIG. . The establishment of unauthorized communication using the repeater 22 means that when a user who possesses the electronic key 2 is far away from the vehicle 1, a third party who attempts the theft relays radio waves using the repeater 22, This is an act of illegally establishing communication (an illegal act using a repeater). The unauthorized communication establishment prevention system 23 of this embodiment is for preventing the establishment of unauthorized communication using the repeater 22.

By the way, this type of repeater 22 can relay data contents, but cannot relay (copy) radio wave intensity. Therefore, if the received signal strength (RSSI: Received Signal Strength Indication) of the radio wave is confirmed in the electronic key 2, whether smart communication is regular communication via the electronic key 2 or unauthorized communication using the repeater 22. I understand. For this reason, the communication fraud establishment prevention system 23 according to the present embodiment executes the communication correctness determination of the smart communication by confirming the received signal strength of the radio wave in the electronic key 2.

In this case, as shown in FIG. 1, the key control unit 13 of the electronic key 2 has a received signal strength calculating unit 26 that calculates the received signal strength of the received radio wave when the radio wave in the UHF band is received from the verification ECU 9. Is provided. The reception signal strength calculation unit 26 calculates the first reception signal strength RSSI1 by detecting the amplitude of the reception radio wave when the UHF transceiver 15 receives the radio wave. The received signal strength calculation unit 26 corresponds to first received signal strength calculation means.

The key control unit 13 of the electronic key 2 is provided with a reception signal strength notification unit 27 that notifies the vehicle 1 of the first reception signal strength RSSI1 calculated by the reception signal strength calculation unit 26.
When the electronic key 2 transmits various radio waves (hereinafter collectively referred to as the UHF radio wave 28) in response to the inquiry of the vehicle 1, the received signal strength notification unit 27, in addition to the main data 29 of the UHF radio wave 28, Received signal strength information 30, which may be a digital data value representing the first received signal strength RSSI 1 of the received radio wave, is placed on the UHF radio wave 28. In the present embodiment, the main data 29 is the ID code 21b and the response code 21a. The reception signal strength notification unit 27 corresponds to a first transmission execution unit.

On the other hand, as shown in FIG. 1, when the vehicle 1 transmits various radio waves in the UHF band (hereinafter collectively referred to as UHF radio wave 24) to the electronic key 2 during smart communication, the verification ECU 9 transmits this UHF radio wave. A transmission processing unit 25 for transmitting 24 in the same frequency band is provided. The transmission processing unit 25 corresponds to a second transmission execution unit.

In addition, the verification ECU 9 is provided with a received signal strength calculation unit 9a that calculates a second received signal strength RSSI2 that is a received signal strength of the received radio wave when a UHF band radio wave is received from the electronic key 2. . The received signal strength calculator 9a corresponds to a second received signal strength calculator.

Further, the verification ECU 9 receives the received signal strength information 30 (first received signal strength RSSI1) notified by the radio wave in the UHF band from the electronic key 2 and the second received signal when the received signal strength information 30 is received. A calculating unit 9b that calculates a difference from the received signal strength RSSI2 is provided. The calculation unit 9b corresponds to calculation means.

In addition, the verification ECU 9 is provided with a communication correctness determination unit 31. The communication correctness determination unit 31 compares the difference with a reference value R registered in advance, and determines whether smart communication with the electronic key 2 is regular communication based on the comparison result. The communication correctness determination unit 31 corresponds to a communication correctness determination unit, and the difference corresponds to a determination value.

(Regarding reference value R)
The reference value R is registered in a memory (not shown) of the verification ECU 9 as follows.
The first received signal strength RSSI1 when the electronic key 2 receives a radio wave (received signal) in the UHF band from the vehicle 1 in communication when registering the ID code 21b or the encryption key of the electronic key 2 in the verification ECU 9 Is calculated by the received signal strength calculating unit 26, and the received signal strength notifying unit 27 notifies the vehicle 1 of the calculated first received signal strength RSSI1. At this time, the received signal strength information 30 is notified by using a radio wave or the like when notifying the ID code 21b and the encryption key.

The second received signal strength RSSI2 of the UHF band radio wave carrying the received signal strength information 30 is calculated by the received signal strength calculating unit 9a, and the first received signal strength transmitted from the electronic key 2 by the calculating unit 9b. The difference between RSSI1 and the second received signal strength RSSI2 calculated by the received signal strength calculator 9a is calculated. Using this difference as a reference value R, the verification ECU 9 registers it in a memory (not shown).

Note that the frequency band of the radio wave in the UHF band at the time of registration of the reference value R is the same frequency band as that of the smart communication. Here, when registering the ID code 21b of the electronic key 2 or the encryption key, the electronic key 2 is in a position close to the vehicle 1 or in a vehicle interior, and does not use a repeater. be registered.

(Operation of the first embodiment)
Next, the operation of the unauthorized communication establishment prevention system 23 according to the present embodiment will be described with reference to FIGS.

First, as shown in FIG. 4, it is assumed that the vehicle 1 performs smart communication with the electronic key 2. FIG. 4 is a flowchart of the wireless communication correctness determination in the wireless communication correctness determination system in smart communication. For convenience of explanation, the vehicle ID, the encryption key, and the key number of the vehicle 1 will be described on the premise that they are a proper combination. Further, the reception signal strength calculation unit 26 of the key control unit 13 in the electronic key 2 may be configured to calculate the reception signal strength of the UHF radio wave 24 every time the UHF radio wave 24 is received from the vehicle 1.

Vehicle 1 (verification ECU 9) first transmits a wake signal 16 of an LF band radio wave during smart communication. When the electronic key 2 receives the wake signal 16, the electronic key 2 transmits an ACK signal 17 of a radio wave in the UHF band to the vehicle 1. Next, the vehicle 1 (verification ECU 9) transmits the vehicle ID 18 using the UHF radio wave 24. The electronic key 2 that has received the vehicle ID 18 confirms the establishment of the vehicle ID collation of the vehicle ID 18 of the UHF band radio wave, and then transmits an ACK signal 19 of the UHF band radio wave to the vehicle 1. When vehicle 1 (verification ECU 9) receives ACK signal 19, it transmits challenge 20 as request signal Srq (UHF radio wave 24) carrying challenge code 20a and key number 20b. The electronic key 2 that has received the challenge 20 carries the response 21 that is the UHF radio wave 28 with the main data 29 (the ID code 21b and the response code 21a) and the first received signal strength RSSI1 that is the received signal strength of the challenge 20. It transmits to the vehicle 1. When receiving the response 21 from the electronic key 2, the verification ECU 9 of the vehicle 1 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. If the verification ECU 9 confirms that both verifications have been established, next, in S10, the verification ECU 9 determines whether or not the communication conditions are satisfied.

(Communication conditions)
The communication condition is whether Formula 1 is satisfied.
P1crx (vehicle received power) = P1krx (electronic key received power) + □ (1)
Derivation of the communication condition will be described with reference to FIG. In FIG. 5, r is the distance between both antennas of the vehicle 1 and the electronic key 2.

When communicating from the vehicle 1 to the electronic key 2 using radio waves in the same frequency band,
Vehicle transmission power: P1ctx (dBm)
Vehicle transmit / receive antenna gain: Gc (dBm)
Propagation loss in free section: Lr (dBm)
Electronic key transmit / receive antenna gain: Gk (dBm)
Electronic key received power: P1krx (dBm)
Then,
P1ctx + Gc−Lr + Gk = P1krx (2)
The received power P1krx of the electronic key is an approximate value of the first received signal strength RSSI1 at the electronic key.

On the other hand, when communicating from the electronic key 2 to the vehicle 1,
Electronic key transmission power: P1ktx (dBm)
Electronic key transmit / receive antenna gain: Gk (dBm)
Propagation loss in free section: Lr (dBm)
Vehicle transmit / receive antenna gain: Gc (dBm)
Vehicle received power: P1crx (dBm)
Then,
P1ktx + Gk−Lr + Gc = P1crx (3)
The received power P1crx of the vehicle is an approximate value of the second received signal strength RSSI2 in the vehicle. Here, the transmission / reception antenna gain Gc of the vehicle and the transmission / reception antenna gain Gk of the electronic key have the relationship of Equation 4,
Gc = Gk + □ (dBm) (4)
The total power P0 at the transmission / reception antenna is the same for both the vehicle and the electronic key. That is,
P0 = P1ctx + Gc = P1ktx + Gk (5)
Then,
P1ctx (Vehicle transmission power) = P1ktx (Electronic key transmission power)-□ (6)
It becomes. □ represents the difference.

Also,
Gc = Gk + □ (dBm) (7)
so,
P1crx (vehicle received power) + Gc = P1krx (electronic key received power) + Gk (8)
Then, the equation 1 is obtained.

From the above, P1ctx (transmission power of the vehicle) and P1ktx (transmission power of the electronic key) have a constant difference □ of the received signal strength between the vehicle and the electronic key when the frequency band is constant.
Therefore, if the difference □ is always constant, Equation 1 is established.

In this embodiment, in order to determine whether Formula 1 is satisfied, the verification ECU 9 calculates the second received signal strength RSSI2 of the response 21 by the received signal strength calculating unit 9a, and the second received signal of the response 21 is calculated. The calculation unit 9b calculates the difference between the strength RSSI2 and the received signal strength information 30 (first received signal strength RSSI1) notified by the response 21. And the communication correctness determination part 31 determines communication correctness by comparing the reference value R and the said difference. In the present embodiment, the fact that the difference matches the reference value R corresponds to the difference being in the reference range.

In addition, in the comparison between the reference value R and the difference □, if the reference value R and the difference □ are the same value, it may be determined that the communication is proper communication with no repeater use fraud. When □ is within the range of R−Δ ≦ □ ≦ R + Δ (that is, the reference range), it may be determined that the difference is constant and it is determined that the communication is proper without any repeater use fraud. Note that Δ is a value that it may be determined that there is no fraudulent use of the repeater.

In S10 of FIG. 4, when Expression 1 is satisfied (that is, when it is established), the verification ECU 9 determines that smart communication is regular communication and processes smart verification (external vehicle verification) as established, and in S20, Permit or execute door locking / unlocking by the door lock device 6.

On the other hand, as shown in FIG. 6, when radio waves are relayed by the relay 22 using the one-side relay method, the operation range is determined by the electronic key 2 from the vehicle 1, so when communication is performed via the relay 22, Equation 1 is not satisfied. For this reason, it is possible to detect fraudulent use of the repeater.

In FIG. 6, Gr is the gain of the antenna of the repeater 22, P1rtx is the transmission power of the repeater 22, and P1rrx is the received power of the repeater 22. Lx is a propagation loss due to the distance x between the repeater 22 and the vehicle 1, and Ly is a propagation loss due to the distance y between the repeater 22 and the electronic key 2.

Further, when radio waves are relayed by the repeater 22 by the bidirectional relay method, the antenna gain Gc, Gr, Gk involved in the communication from the vehicle 1 to the electronic key 2 and the communication from the electronic key 2 to the vehicle 1 are used. If the involved antenna gains Gc, Gr, and Gk are not equal, the difference □ of the received signal strength is not constant, and Equation 1 is not satisfied. That is, when relaying radio waves by such a bidirectional relay system, it is difficult to create a repeater that makes the gain related to the forward path equal to the gain related to the return path. Therefore, it is possible to easily detect fraudulent use of the repeater.

As described above, when the expression 1 is not satisfied in S10 (that is, when it is not established), the verification ECU 9 determines that the smart communication is an unauthorized communication, and in S30, the smart verification (external vehicle verification) is determined not to be established. To process.

As described above, in this embodiment, the vehicle 1 and the electronic key 2 perform smart communication using the UHF radio wave 24 and the UHF radio wave 28 in the same frequency band. Then, the electronic key 2 calculates the first received signal strength RSSI1 when the radio wave from the vehicle 1 is received. In the electronic key 2, the calculated first received signal strength RSSI 1 is transmitted to the vehicle 1 as received signal strength information 30. The vehicle 1 calculates the second received signal strength RSSI2 of the radio wave carrying the received signal strength information 30, and calculates the difference between the received signal strength information 30 (first received signal strength RSSI1) and the calculated second received signal strength RSSI2. If the difference is the same as the reference value, the smart communication is processed as a regular communication. On the other hand, if the difference is not the same, the smart communication is processed as an unauthorized communication using the repeater 22. Therefore, since it is possible to identify unauthorized communication using the repeater 22, it is possible to prevent the unauthorized communication from being processed as established.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) The vehicle 1 and the electronic key 2 communicate with each other using UHF radio waves in the same frequency band, and the electronic key 2 calculates the first received signal strength RSSI1 of the radio wave 24 from the vehicle 1 and receives the received signal indicating the received signal strength. The strength information 30 is transmitted to the vehicle 1. Then, the vehicle 1 calculates the difference between the received signal strength information 30 (first received signal strength RSSI1) received from the electronic key 2 and the second received signal strength RSSI2 of the radio wave 28 on which the received signal strength information 30 is carried. Whether or not the smart communication is correct is determined by checking whether or not the difference is the same as the reference value. For this reason, since it becomes possible to distinguish whether smart communication is communication using the repeater 22, it is difficult to establish unauthorized communication using the repeater 22. Therefore, security against unauthorized use or theft of the vehicle 1 can be ensured.

(2) Since authentication of smart communication is performed by the vehicle 1, it is not necessary to newly provide this kind of authentication function in the electronic key 2. Therefore, the electronic key 2 used so far can be used as it is, and the electronic key 2 can have a simple structure.

(3) Since the determination value compared with the reference value to determine whether or not regular communication is the difference between the first received signal strength RSSI1 and the second received signal strength RSSI2, whether or not regular communication is performed quickly with a simple calculation Can be determined.

(Second Embodiment)
Next, the communication fraud establishment preventing system 23 employed in the key operation free system 3 of the second embodiment will be described with reference to FIG. In the present embodiment, the configuration different from that of the first embodiment will be mainly described, and the same or corresponding configurations as those of the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted. In the present embodiment, as in the first embodiment, UHF radio waves used for communication between the vehicle 1 and the electronic key 2 are in the same frequency band. Moreover, the type of UHF radio wave of each embodiment including this embodiment is not limited.

In the present embodiment, the key control unit 13 of the electronic key 2 is different from the first embodiment in that a comparison unit 13a is provided.
The comparison unit 13a compares the first reception signal strength RSSI1 of the UHF radio wave transmitted from the vehicle 1 calculated by the reception signal strength calculation unit 26 with a first threshold value for detection of reception signal strength saturation. Note that the first threshold value is slightly lower than the saturation value (maximum value) of the received signal strength of UHF radio waves that can be processed by, for example, the circuit inside the UHF transceiver 15. When the first received signal strength RSSI1 exceeds the first threshold for detecting the received signal strength saturation, the comparison unit 13a determines that the first received signal strength RSSI1 of the received radio wave is saturated. When this determination is made, the reception signal strength notification unit 27 notifies the vehicle 1 of the first reception signal strength RSSI1 and the attenuation request that are saturated with UHF radio waves. If it is determined that the UHF radio wave from the vehicle 1 is saturated, the electronic key 2 is transmitted as a response to the UHF radio wave to be notified.

Here, the comparison unit 13a corresponds to a first comparison unit, and the attenuation request corresponds to a first attenuation request.
When the verification ECU 9 of the vehicle 1 receives the first reception signal strength RSSI1 and the attenuation request, the transmission processing unit 25 performs power control so that the transmission output is attenuated from the previous output based on them, and the electronic key 2 Send UHF radio waves to In this case, the attenuation α of the transmission output is a preset amount.

Note that the verification ECU 9 of the vehicle 1 performs the same processing as described above every time it receives the first received signal strength RSSI1 and the attenuation request.
When the calculation unit 9b receives the notification of the first received signal strength RSSI1 without the attenuation request from the electronic key 2 after the above processing, the calculation unit 9b receives the second received signal of the radio wave itself without the attenuation request. The difference between the strength RSSI2 and the new first received signal strength RSSI1 notified by the radio wave is calculated.

In this case, the communication correctness determination unit 31 compares the reference value changed from R to R + n · α with the difference calculated by the calculation unit 9b according to the number of times the transmission output is attenuated by the attenuation amount α. Then, the communication correctness is determined.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When the vehicle 1 and the electronic key 2 are close to each other, the received signal intensity of the radio wave received by the electronic key 2 may be saturated. In this case, in the present embodiment, the electronic key 2 requests the verification ECU 9 of the vehicle 1 to attenuate the transmission output of the radio wave, so that the received signal strength of the radio wave received by the electronic key 2 is not saturated. With this saturation disappearing, it is possible to determine whether the smart communication is correct or not. As a result, the same effect as the first embodiment is obtained.

(Third embodiment)
Next, the communication fraud establishment prevention system 23 employed in the key operation free system 3 of the third embodiment will be described with reference to FIG. In the present embodiment, the configuration different from that of the first embodiment will be mainly described, and the same or corresponding configurations as those of the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted. In the present embodiment, as in the first embodiment, UHF radio waves used for communication between the vehicle 1 and the electronic key 2 are in the same frequency band.

In the present embodiment, the comparison ECU 9 of the vehicle 1 is different from the first embodiment in that a comparison unit 9c is provided.
The comparison unit 9c compares the second received signal strength RSSI2 of the UHF radio wave from the electronic key 2 calculated by the received signal strength calculating unit 9a with the second threshold value for detecting the received signal strength saturation, and compares the second received signal strength. When RSSI2 exceeds the second threshold for detection of received signal strength saturation, it is determined that the received signal strength of the received radio wave is saturated. Note that the second threshold value is slightly lower than the saturation value (maximum value) of the received signal strength of UHF radio waves that can be processed by, for example, the circuit inside the UHF transceiver 12.

The transmission processing unit 25 transmits the attenuation request and the second received signal strength RSSI2 exceeding the second threshold to the electronic key 2. Here, the comparison unit 9c corresponds to a second comparison unit, and the attenuation request corresponds to a second attenuation request.

The reception signal strength notification unit 27 of the electronic key 2 performs power control so that the transmission output is attenuated from the previous output based on the attenuation request and the second reception signal strength RSSI2 exceeding the second threshold, and the vehicle Send radio waves to 1. In this case, the attenuation β of the transmission output is a preset amount. The attenuation amount β may be the same as or different from the attenuation amount α of the second embodiment.

Every time the electronic key 2 receives the attenuation request and the second received signal strength RSSI2 that exceeds the second threshold, the same process as described above is performed.
The calculation unit 9b of the verification ECU 9 of the vehicle 1 performs a challenge 20 in which the transmission processing unit 25 does not include the attenuation request immediately after or after transmitting the attenuation request and the second received signal strength RSSI2 exceeding the second threshold. A difference between the new second received signal strength RSSI2 of the radio wave itself transmitted from the electronic key 2 and the first received signal strength RSSI1 notified by the radio wave for which the new second received signal strength RSSI2 is calculated calculate. The communication correctness determination unit 31 then changes the reference value changed from R to R + m · β according to the number m of transmission output attenuation by the attenuation amount β (that is, the number of attenuation requests) and the difference calculated by the calculation unit 9b. To determine whether the communication is correct.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When the vehicle 1 and the electronic key 2 are close to each other, the received signal intensity of the radio wave received by the verification ECU 9 may be saturated. In this case, in this embodiment, the verification ECU 9 requests the electronic key 2 to attenuate the transmission output of the radio wave, so that the received signal intensity of the radio wave received by the verification ECU 9 can be prevented from being saturated. With this saturation disappearing, it is possible to determine whether the smart communication is correct or not. As a result, the same effect as the first embodiment is obtained.

(Fourth embodiment)
Next, the communication fraud establishment preventing system 23 employed in the key operation free system 3 of the fourth embodiment will be described with reference to FIG. The fourth embodiment is a combination of the second embodiment and the third embodiment. That is, in this embodiment, as shown in FIG. 9, the key operation free system 3 and the communication fraud establishment prevention system 23 are configured by the electronic key 2 having the comparison unit 13a and the verification ECU 9 having the comparison unit 9c. . This unauthorized communication establishment prevention system 23 has the effects described in the second embodiment and the third embodiment.

In the fourth embodiment, in the case of n · attenuation amount α ≠ m · attenuation amount β, the communication correctness determination unit 31 determines the transmission output from R according to the amount of attenuation by the vehicle 1 and the electronic key 2 respectively. Whether the communication is correct or not is determined by comparing the reference value changed to R + n · α−m · β and the difference calculated by the calculation unit 9b.

In addition, when n · attenuation amount α = m · attenuation amount β, the communication correctness determination unit 31 sets the reference value as R, and compares the reference value R with the difference calculated by the calculation unit 9b. Judgment of communication correctness is performed.

The first to fourth embodiments are not limited to the configurations described so far, and may be modified as follows.
In each of the above embodiments, the received signal strength information 30 is put on the response 21, but in the UHF radio wave 28 transmitted from the electronic key 2, the radio wave on which the received signal strength information 30 is put is the ACK signals 17 and 19, the response described above. 21 may be used, and other types of UHF radio waves may be used. Then, the second received signal strength RSSI2 of the radio wave carrying the received signal strength information 30 is calculated by the received signal strength calculating unit 9a, the difference is calculated by the calculating unit 9b, and then the communication correctness determining unit 31 calculates the reference value R and The difference □ may be compared.

In each of the above embodiments, the received signal strength of the radio wave carrying the received signal strength information 30 is the second received signal strength RSSI2, but the received signal strength of the radio wave from the electronic key 2 not including the received signal strength information 30 is It is good also as 2nd received signal strength RSSI2.

In each of the above embodiments, when the difference between the second received signal strength RSSI2 of the response 21 and the first received signal strength RSSI1 (received signal strength information 30) of the challenge 20 is different from the reference value R once. , It was not regular communication.

Instead of this, in the communication of various radio waves between the vehicle 1 and the electronic key 2, the second received signal of the radio wave that has been communicated a plurality of times and the vehicle 1 has been notified of the first received signal strength RSSI1 (received signal strength information 30). Even if the difference between the strength RSSI2 and the first received signal strength RSSI1 is not the same as the reference value and the difference becomes constant after the determination by the communication correctness determination unit 31, the difference is constant. Good.

In the second embodiment, when the UHF radio wave transmitted from the vehicle 1 is saturated, the electronic key 2 sends the attenuation request (first attenuation request) and the first received signal strength RSSI1 at that time to the vehicle 1. Although transmitted, only the attenuation request (first attenuation request) may be transmitted to the vehicle 1. In this case, the transmission processing unit 25 in the verification ECU 9 of the vehicle 1 attenuates the transmission output of the UHF radio wave based on this attenuation request.

In the third embodiment, when the UHF radio wave transmitted from the electronic key 2 is saturated, the vehicle 1 sends the attenuation request (second attenuation request) and the second received signal strength RSSI2 at that time to the electronic key 2. However, only the attenuation request (second attenuation request) may be transmitted to the electronic key 2. In this case, the reception signal strength notification unit 27 of the electronic key 2 attenuates the transmission output of the UHF radio wave based on this attenuation request.

(Fifth embodiment)
Next, a communication fraud establishment prevention system 23 employed in the key operation free system 3 of the fifth embodiment will be described with reference to FIGS. 10 and 11 with reference to FIG. In the present embodiment, as in the first embodiment, UHF radio waves used for communication between the vehicle 1 and the electronic key 2 are in the same frequency band.

This embodiment is different from the first embodiment in that the determination value is the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength.
As shown in FIG. 10, it is assumed that the vehicle 1 performs smart communication with the electronic key 2. The reception signal strength calculation unit 26 of the key control unit 13 in the electronic key 2 associates the first reception signal strength of the UHF radio wave 24 with the reception time each time the UHF radio wave 24 is received from the vehicle 1. Assume that it is calculated. Therefore, the received signal strength calculation unit 26 corresponds to first received signal strength calculation means. Further, every time the UHF radio wave 28 is received from the electronic key 2, the received signal strength calculation unit 9 a of the verification ECU 9 in the vehicle 1 calculates the second received signal intensity of the UHF radio wave 28 in association with the reception time. It shall be. Therefore, the received signal strength calculating unit 9a corresponds to a second received signal strength calculating unit. As a result, in both the vehicle 1 and the electronic key 2, a temporal change in the received signal strength of the UHF radio wave from the other party can be obtained.

Vehicle 1 (verification ECU 9) first transmits a wake signal of an LF band radio wave during smart communication. When the electronic key 2 receives the wake signal, the electronic key 2 transmits an UHF band radio wave ACK signal to the vehicle 1.

Thereafter, the vehicle 1 (verification ECU 9) transmits the first challenge by the UHF radio wave 24. The electronic key 2 that has received the first challenge is calculated by associating the first received signal strength RSSIkey1 (referred to as B1 for convenience) at the time of receiving the first challenge with the reception time of the first challenge, In this example, a first response that is a UHF radio wave 28 not including the first received signal strength RSSIkey 1 is transmitted to the vehicle 1. When the first response is received, the verification ECU 9 of the vehicle 1 calculates the second received signal strength RSSIcar1 (referred to as A1 for convenience) when the first response is received in association with the first response reception time. Above, the second challenge by UHF radio wave 24 is transmitted.

The electronic key 2 that has received the second challenge calculates the first received signal strength RSSIkey2 (referred to as B2 for convenience) when the second challenge is received in association with the reception time of the second challenge, In this example, a second response that is a UHF radio wave 28 not including the first received signal strength RSSIkey 2 is transmitted to the vehicle 1. When the second response is received, the verification ECU 9 of the vehicle 1 calculates the second received signal strength RSSIcar2 (referred to as A2 for convenience) at the time of receiving the second response in association with the reception time of the second response. Above, a third challenge (not shown) by the UHF radio wave 24 is transmitted.

Eventually, the electronic key 2 that has received the n-th challenge is calculated by associating the first received signal strength RSSIkeyn (referred to as Bn for convenience) when the n-th challenge is received with the reception time of the n-th challenge. Thus, in this example, the nth response which is the UHF radio wave 28 not including the first received signal strength RSSIkeyn is transmitted to the vehicle 1. When the verification ECU 9 of the vehicle 1 receives the n-th response, the verification ECU 9 calculates the second received signal strength RSSIcarn (referred to as An for convenience) when the n-th response is received in association with the reception time of the n-th response. .

The electronic key 2 transmits the n-th response to the vehicle 1 after the transmission and reception of the challenge and response between the vehicle 1 and the electronic key 2 are repeated n times. UHF radio wave 28 carrying first received signal strength information RSSIkeym including all B1 to Bn is transmitted to vehicle 1.

In S40, the verification ECU 9 of the vehicle 1 calculates a correlation coefficient ρ (−1 ≦ ρ ≦ 1) indicating the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength. The correlation coefficient ρ corresponds to a determination value, and the calculation unit 9b of the verification ECU 9 corresponds to a calculation unit. Here, the second received signal strength measured by the vehicle 1 is A = [A1, A2,..., An], and the first received signal strength measured by the electronic key 2 is B = [B1, B2,. .., Bn]. In FIG. 11, the second received signal strength measured by the vehicle 1 is plotted with a mark “x”, and the first received signal strength measured with the electronic key 2 is plotted with a mark “◯”. Time change is shown.

Returning to the calculation of the correlation coefficient ρ, the average value of the second received signal strength is a = ΣAm / n (where m = 1, 2,..., N), and the average value of the first received signal strength is b. = ΣBm / n (where m = 1, 2,..., N). Then, the difference between the second received signal strength and its average value is A ′ = [A1-a, A2-a,..., An−a], and the difference between the first received signal strength and its average value is B ′ = [B1-b, B2-b,..., Bn−b].

The Pearson correlation coefficient ρ is calculated using the following equation 9 (S40).

The verification ECU 9 of the vehicle 1 determines whether or not the correlation coefficient ρ is close to 1 in S50. The closer the correlation coefficient ρ is to 1, the higher the correlation is, and the time change of the first received signal strength and the time change of the second received signal strength are approximately the same, that is, the time changes of the first and second received signal strengths. The curve is similar. Conversely, as the correlation coefficient ρ is closer to 0, there is no correlation, and the time change curves of the first and second received signal strengths are far from the similar shape. In S50, it is determined whether or not the correlation coefficient ρ is within a reference range for determining the degree of coincidence. The upper limit of this reference range is 1, and the lower limit is, for example, 0.95.

If the verification ECU 9 of the vehicle 1 determines YES in S50, it permits or executes door locking / unlocking in S60, while if it determines NO in S50, it performs smart verification (S70) while detecting unauthorized use of the repeater in S70. (External vehicle verification) is processed as not established. The communication correctness determination unit 31 of the verification ECU 9 corresponds to communication correctness determination means.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) Since the two-way communication between the verification ECU 9 and the electronic key 2 of the vehicle 1 is performed using UHF radio waves in the same frequency band, the positional relationship and radio waves between the two are not dependent on the antenna directivity and the distance between the two. Even if the propagation environment changes, the determination value indicating the degree of coincidence between the temporal change in the first received signal strength and the temporal change in the second received signal strength is within the reference range. On the other hand, when communication is performed between the verification ECU 9 and the electronic key 2 via the repeater 22, the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength is determined. The judgment value shown does not fall within the reference range. Therefore, it is possible to determine whether or not the normal communication is performed by comparing the correlation coefficient ρ, which is a determination value indicating the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength, with the reference range. it can. As a result, it is possible to distinguish whether the smart communication is a communication using the repeater 22, so that it is difficult to establish an unauthorized communication using the repeater 22. Therefore, security against unauthorized use or theft of the vehicle 1 can be ensured.

(2) Since the electronic key 2 collectively transmits information on the first received signal strengths of a plurality of reception opportunities, each time the electronic key 2 receives a radio wave from the verification ECU 9, the first received signal of the received radio wave Each response radio wave can be simplified when transmitting a response radio wave to the radio wave from the verification ECU 9 as compared with the case of transmitting the intensity information.

(3) When the electronic key transmits information on the first received signal strength of the received radio wave every time a radio wave is received from the verification ECU 9, the verification ECU 9 receives the first received signal strength information. Until the next radio wave may not be transmitted. However, in this embodiment, since this inconvenience does not occur, bidirectional communication can be performed smoothly.

(4) In relation to (1) above, it is possible to detect fraudulent use of the repeater even if the user with the electronic key 2 moves.
(5) When the repeater 22 is used in the one-sided relay system, one of the paths is different, and therefore, this embodiment can detect a fraudulent use of the relay in the one-sided relay system.

(6) In the case of the bidirectional relay system using a different frequency band, since both paths are different, the present embodiment can detect the illegal use of the relay apparatus of the bidirectional relay system.
(7) Acquisition (exchange) of the first received signal strength when registering the electronic key 2 in the verification ECU 9 is not necessary.

The fifth embodiment is not limited to the configuration described so far, and may be modified as follows.
Instead of using Pearson's correlation coefficient ρ as a determination value, a cross-correlation coefficient may be used. Alternatively, the least square method, Fourier transform, wavelet transform may be used, or image processing technology (image coincidence detection, etc.) may be applied.

Instead of transmitting the information of the first received signal strengths of a plurality of reception opportunities all together, the first received signal of the received radio wave is received every time the UHF radio wave 24 from the verification ECU 9 is received with reference to FIG. The UHF radio wave 28 carrying the strength information (received signal strength information 30) may be transmitted to the vehicle 1. In this case, the received signal strength information 30 is information on the first received signal strength associated with the reception time of the UHF radio wave 24. As a result, the verification ECU 9 of the vehicle 1 can obtain the time change of the second received signal strength while calculating the second received signal strength of the UHF radio wave 28 in association with the reception time, and is included in the UHF radio wave 28. Based on the received signal strength information 30, a time change of the first received signal strength can be obtained (similar to FIG. 11). Then, the calculation unit 9b of the verification ECU 9 receives the UHF radio wave 28 including the received signal strength information 30 (every reception opportunity), collects every plural times, or after the last n times Collectively, the correlation coefficient ρ is calculated.

(Sixth embodiment)
Next, a sixth embodiment of the communication fraud establishment preventing system 23 will be described with reference to FIGS. Also in this embodiment, UHF radio waves used for communication between the vehicle 1 and the electronic key 2 are in the same frequency band. The communication fraud establishment prevention system 23 including the key verification device 5 and the electronic key 2 is a wireless communication right / fail judgment system that prevents the smart communication fraud.

In the present embodiment, as in the fifth embodiment, the degree of coincidence between the time change of the first received signal strength RSSI1 and the time change of the second received signal strength RSSI2 is used as the determination value.
As shown in FIG. 12, the UHF transceiver 12 of the vehicle 1 includes two antennas 12a and 12b and a switching unit 12c. The UHF transmitter / receiver 12 transmits the UHF radio wave 24 to the electronic key 2 using either one of the two antennas 12a and 12b. Further, the UHF transceiver 12 receives the UHF radio wave 28 from the electronic key 2 by using one of the two antennas 12a and 12b. During the communication between the vehicle 1 and the electronic key 2, the switching unit 12c switches between the antenna 12a and the antenna 12b for an antenna that transmits and receives UHF band radio waves. In addition, it is preferable that the antennas 12a and 12b are provided in the vehicle 1 as far away as possible.

The UHF transceiver 15 of the electronic key 2 includes an antenna 15a.
As shown in FIG. 13, the vehicle 1 (collation ECU 9) first transmits a wake signal based on radio waves in the LF band during smart communication. When the electronic key 2 receives the wake signal, the electronic key 2 transmits an ACK signal based on a radio wave in the UHF band to the vehicle 1.

Thereafter, as in the fifth embodiment, transmission / reception of a challenge (CH) and a response (Re) by radio waves in the UHF band is repeated n times between the verification ECU 9 of the vehicle 1 and the electronic key 2. That is, the verification ECU 9 transmits a challenge by the UHF radio wave 24 to the electronic key 2 n times, and the electronic key 2 transmits a response by the UHF radio wave 28 to the verification ECU 9 n times as a response to the challenge of n times. The electronic key 2 calculates the first received signal strengths RSSIkey1 to RSSIkeyn (referred to as B1 to Bn for convenience) of the received n challenges in association with the reception time of the challenge. The verification ECU 9 calculates the second received signal strengths RSSIcar1 to RSSIcarn (referred to as A1 to An for convenience) of the received n responses in association with the response reception time.

When transmission / reception of a challenge and a response is repeated n times between the vehicle 1 and the electronic key 2, the electronic key 2 transmits the nth response to the vehicle 1 and then includes the first B1 to Bn. The UHF radio wave 28 carrying the received signal strength information RSSIkeym is transmitted to the vehicle 1. The vehicle 1 stores the calculated A1 to An.

By the way, in this embodiment, while the transmission and reception of the challenge and the response are repeated n times between the vehicle 1 and the electronic key 2, the switching unit 12c switches the antenna that transmits and receives the UHF radio wave. As an example, transmission / reception between the vehicle 1 and the electronic key 2 is performed using the antenna 12a and without using the antenna 12b from the first time to the kth time (k <n). When the verification ECU 9 receives the k-th response, the switching unit 12c switches the antenna used for transmission / reception between the vehicle 1 and the electronic key 2 from the antenna 12a to the antenna 12b. The transmission / reception between the vehicle 1 and the electronic key 2 is performed without using the antenna 12a using the antenna 12b from the (k + 1) th time to the nth time.

In S80, the verification ECU 9 of the vehicle 1 calculates the correlation coefficient ρ indicating the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength by using Equation 9.
In S90, the verification ECU 9 of the vehicle 1 determines whether or not the correlation coefficient ρ is close to 1, that is, whether or not the temporal change in the first received signal strength matches the temporal change in the second received signal strength. to decide. In particular, it is preferable to confirm the degree of coincidence between the temporal change in the first received signal strength and the temporal change in the second received signal strength in a certain period immediately after switching the antenna by the switching unit 12c. This is because immediately after the switching unit 12c switches the antenna, the first received signal strength and the second received signal strength vary greatly.

If the verification ECU 9 of the vehicle 1 determines YES in S90, it permits the door lock device 6 to lock and unlock the door in S100, while if it determines NO in S90, it detects an illegal act of using the repeater in S110. In-car smart verification is treated as not established.

Next, a communication path in wireless communication between the vehicle 1 and the electronic key 2 will be described. Here, it is assumed that the vehicle 1 and the electronic key 2 are stationary.
First, a comparative example will be described. As shown in FIG. 14A, a repeater 22 is provided on the communication path between the vehicle 1 and the electronic key 2. Here, the UHF radio wave transmitted from the vehicle 1 reaches the electronic key 2 via the repeater 22. Therefore, UHF radio waves transmitted from the antenna 15a of the electronic key 2 reach the vehicle 1 directly, whereas UHF radio waves transmitted from the antenna 12a of the vehicle 1 are transmitted via the antenna 22a of the repeater 22 to the electronic key 2 Reaches the antenna 15a. When the vehicle 1 and the electronic key 2 are stationary, the positional relationship and the propagation environment between the vehicle 1 and the electronic key 2 do not change. Further, even when communication between the vehicle 1 and the electronic key 2 is performed via the repeater 22, the positional relationship between the vehicle 1 and the electronic key 2 and the propagation environment as long as the repeater 22 does not move. Does not change. That is, the propagation path of the radio wave between the vehicle 1 and the electronic key 2 does not change.

As shown in FIG. 15 (a), when the vehicle 1 and the electronic key 2 are stationary, the first received signal strength indicated by the solid line and the second received signal strength indicated by the two-dot chain line are It is constant regardless of the course. Note that the communication path from the vehicle 1 to the electronic key 2 via the repeater 22 and the communication path from the electronic key 2 to the vehicle 1 not via the repeater 22 differ in the propagation distance and propagation environment of radio waves. The first received signal strength and the second received signal strength exhibit similar time changes (trajectories) in a state where they deviate from each other by a certain amount.

On the other hand, as shown in FIG. 14B, in this embodiment, the vehicle 1 and the electronic key 2 are in a stationary state by switching the antennas 12a and 12b provided in the vehicle 1. In addition, the propagation path of the radio wave between the vehicle 1 and the electronic key 2 can be changed. That is, the UHF radio wave transmitted from the antenna 12a reaches the antenna 15a via the antenna 22a as indicated by a solid line. Further, the UHF radio wave transmitted from the antenna 12b reaches the antenna 15a via the antenna 22a as indicated by a broken line. For this reason, the communication path to the antenna 15a differs between the antenna 12a and the antenna 12b. Thereby, although the positional relationship between the repeater 22 and the electronic key 2 does not change, the propagation path of the radio wave between the vehicle 1 and the repeater 22 is changed from the path between the antenna 12a and the antenna 22a to the antenna. It changes by the amount of switching to the path between 12b and the antenna 22a. Simply, it is considered that the closer the vehicle 1 and the repeater 22 are, the greater the received signal strength of the UHF radio wave that reaches the repeater 22 and the greater the first received signal strength calculated by the electronic key 2. In addition, while there is an obstacle between the antenna 12a and the antenna 22a that interferes with the UHF radio wave, when there is no obstacle between the antenna 12b and the antenna 22a that interferes with the UHF radio wave, the antenna 12a to the antenna By switching to 12b, the propagation environment of the UHF radio wave to the antenna 22a can be changed. As a result, the first received signal strength calculated by the electronic key 2 changes.

Also, the communication path from the electronic key 2 to the vehicle 1 is switched from the antenna 12a to the antenna 12b, so that the propagation path of the radio wave between the vehicle 1 and the electronic key 2 changes, so that the vehicle 1 The second received signal strength calculated by the verification ECU 9 changes.

As shown in FIG. 15 (b), when the vehicle 1 and the electronic key 2 are stationary, the first reception signal strength indicated by the solid line is also indicated by the two-dot chain line until the antenna is switched. The signal intensity is also a constant value regardless of the passage of time. For this reason, the time change of the first received signal strength matches the time change of the second received signal strength because the time change of the second received signal strength matches the time change of the second received signal strength. It is difficult to determine whether or not the communication between the vehicle 1 and the electronic key 2 is an unauthorized communication using the repeater 22 only by the degree.

However, in the present embodiment, the vehicle 1 is switched by switching the antenna of the vehicle 1 during bidirectional communication between the vehicle 1 and the electronic key 2 (during measurement of the first received signal strength and the second received signal strength). Even when the electronic key 2 is stationary, the first received signal strength and the second received signal strength can be changed. As an example, when the antenna of the vehicle 1 is switched, the first received signal strength rapidly increases and the second received signal strength decreases rapidly. That is, the UHF radio wave is transmitted via the repeater 22 when transmitted from the vehicle 1 to the electronic key 2, while not transmitted via the repeater 22 when transmitted from the electronic key 2 to the vehicle 1. Therefore, the tendency of changes in the first received signal strength and the second received signal strength is different. For this reason, immediately after the antenna of the vehicle 1 is switched, the temporal change in the first received signal strength and the temporal change in the second received signal strength do not match (no correlation).

When a certain amount of time elapses after the antenna of the vehicle 1 is switched, the first received signal strength and the second received signal strength again become constant values regardless of the passage of time.
According to the configuration of the present embodiment, the following effects can be obtained.

(1) During bidirectional communication between the verification ECU 9 of the vehicle 1 and the electronic key 2, the switching unit 12c switches the antenna (for example, antenna diversity), thereby propagating radio waves between the vehicle 1 and the electronic key 2. Since the path can be changed, the first received signal strength and the second received signal strength change. When the repeater 22 is not used, even if the propagation path of the radio wave between the vehicle 1 and the electronic key 2 is changed by switching to another antenna, the time change of the first received signal strength and the (2) The time change of the received signal strength changes in a similar manner with almost the same state. In this case, the correlation coefficient ρ, which is a determination value indicating the degree of coincidence between the temporal change in the first received signal strength and the temporal change in the second received signal strength, is almost 1 (there is a correlation). This is because the communication path from the vehicle 1 to the electronic key 2 and the communication path from the electronic key 2 to the vehicle 1 are the same even when the antenna is switched.

On the other hand, when the repeater 22 is used, the time change of the first received signal strength does not coincide with the time change of the second received signal strength by switching to another antenna. The correlation coefficient ρ, which is a determination value indicating the degree of coincidence between the time change of the signal strength and the time change of the second received signal strength, becomes small. As a result, it is possible to distinguish whether the smart communication is unauthorized communication using the repeater 22. It is possible to make it difficult to establish unauthorized communication using the repeater 22 by taking some countermeasures based on whether smart communication is unauthorized communication.

(2) Even when the vehicle 1 and the electronic key 2 are stationary, the time change of the first received signal strength and the time change of the second received signal strength can be changed by switching the antenna. This is because the propagation path between the vehicle 1 and the electronic key 2 changes by switching to another antenna even when the vehicle 1 and the electronic key 2 are stationary. Therefore, even when the vehicle 1 and the electronic key 2 are stationary, the smart communication uses the repeater 22 based on the time change of the first received signal strength and the time change of the second received signal strength. It can be determined whether or not the communication is unauthorized.

The sixth embodiment is not limited to the configuration described so far, and may be modified as follows.
The correlation coefficient indicating the degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength is calculated based on data for a certain time immediately after the antenna is switched, and the correlation coefficient is It may be determined whether the communication between the vehicle 1 and the electronic key 2 is unauthorized communication as a determination value. Further, as a determination value, a correlation coefficient of time change of a difference between the first received signal strength and the second received signal strength may be used. Further, not only the correlation coefficient, but also any determination value may be used as long as it is a determination value for determining whether the time change of the first received signal strength and the time change of the second received signal strength are the same. Good.

Although two antennas 12a and 12b are provided in the vehicle 1, three or more antennas may be provided. In addition, it is preferable that each antenna exists in the position away from each other.
-Although the two antennas 12a and 12b were provided in the vehicle 1, it is not restricted to this. For example, the electronic key 2 may be switched between the antenna 15a and the separate antenna by providing a separate antenna instead of the antenna 15a. Further, both the vehicle 1 and the electronic key 2 may be switched between a plurality of antennas by providing a plurality of antennas.

-The propagation environment between the vehicle 1 and the electronic key 2 is not limited to providing a plurality of antennas 12a and 12b so that the antenna can be physically switched on the vehicle 1 but by changing the directivity of the antenna. It may be changed. For example, as shown in FIG. 16A, the directivity of the antenna 12a is changed by switching the power supply 40 that supplies power to the antenna 12a to the power supply 41 that supplies power having a voltage value different from that of the power supply 40. May be. The switching unit 12c switches the power source to which the antenna 12a is connected between the power source 40 and the power source 41. Thereby, the antenna 12a is switched to an antenna in a different state. Further, the directivity of the antenna 12a may be changed by changing the capacitance or resistance value of the antenna 12a. For example, as shown in FIG. 16B, the directivity of the antenna 12 a may be changed by switching whether or not the coil 42 is interposed between the antenna 12 a and the power supply 40. Thereby, the antenna 12a is switched to an antenna in a different state. Further, as shown in FIG. 16C, the directivity of the antenna 12a may be changed by switching the feeding point between the antenna 12a and the power source 40.

A configuration according to the modified example of the first to fourth embodiments may be combined with the fifth embodiment and the sixth embodiment.
The first to sixth embodiments are not limited to the configurations described so far, and may be modified as follows.

In each of the above embodiments, the electronic key system is not limited to the key operation free system 3, and may be an immobilizer system, for example.
In each of the above embodiments, the frequency band used for bidirectional communication is not limited to the UHF band. For example, other frequency bands such as an LF (Low Frequency) band and an HF (High Frequency) band may be used. Good. In addition, about the radio wave used for bidirectional communication between the vehicle 1 and the electronic key 2, the same frequency band has the same radio wave propagation loss at the time of each communication, and so-called reciprocity theorem (reciprocity theorem) exists between the two. The range of frequencies that can be considered to hold. The reciprocity theorem is a theorem in which the determination value based on the received signal strength of both is constant regardless of the antenna directivity and the distance between the two at the same frequency.

In each of the above embodiments, the communication master is not limited to the verification ECU 9, and may be another ECU that manages communication.
In each of the above embodiments, the communication terminal is not limited to the electronic key 2 and may be any terminal capable of wireless communication.

In the above embodiments, the inquiry is not limited to the request signal Srq, and other signals can be employed. Further, the response is not limited to the ID signal Sid, but may be any signal that the electronic key 2 returns to the vehicle 1.

In each of the above embodiments, the communication fraud establishment prevention system 23 is not limited to being used for the vehicle 1 but can be applied to other devices and apparatuses.
In each of the above embodiments, the first communication unit is a communication terminal (electronic key 2) and the second communication unit is a communication master (verification ECU 9). Conversely, the first communication unit is a communication master (verification ECU 9). The second communication unit may be a communication terminal (electronic key 2). That is, the configuration of the verification ECU 9 of each of the embodiments that performs communication correctness determination on the electronic key 2 side may be provided on the electronic key side.

In each of the above embodiments, either one of the first communication unit and the second communication unit performs the communication correctness determination. However, the configuration of the verification ECU 9 of each embodiment that performs the communication correctness determination is as follows. You may provide in both a 1st communication part and a 2nd communication part.

In each of the above embodiments, various parameters calculated from the received signal strength may be used for determination by machine learning.
The collation ECU 9 includes one or more processors that function as the received signal strength calculation unit 9a, the calculation unit 9b, the transmission processing unit 25, the communication correctness determination unit 31, and optionally the comparison unit 9c, and the one or more processors. And a non-transitory machine-readable storage medium storing instructions to be executed by the computer. Similarly, the key control unit 13 includes a received signal strength calculating unit 26, a received signal strength notifying unit 27, and optionally one or more processors functioning as a comparing unit 13a, and the one or more processors. And a non-transitory machine-readable storage medium storing instructions to be executed. The non-transitory machine-readable storage medium may be a nonvolatile memory, a magnetic disk device including a magnetic disk, an optical disk device including an optical disk, or the like.

The present disclosure includes the following implementation examples. For ease of understanding rather than limitation, the reference numerals of the illustrated embodiments are provided.
One or more implementation examples of the present invention include a master communicator (5) that transmits a query (Srq) using a first radio wave (24) and a response (Sid) that responds to the query (Srq) as a second radio wave (28). A system for unlocking the vehicle (1) through two-way wireless communication with the client communication device (2) transmitting in the same frequency band is provided. The system causes one or more processors provided in the master communicator (5) and / or the client communicator (2) to perform the method when executed by the one or more processors. A non-transitory machine-readable storage medium storing instructions. In the method, the one or more processors calculate a first received signal strength that is a received signal strength of the first radio wave (24) received by the client communication device (2) from the master communication device (5). The client communicator (2) transmits the first received signal strength (30) to the master communicator (5) by the second radio wave (28), and the master communicator (5) The one or more processors calculate a second received signal strength that is a received signal strength of the second radio wave (28) received from the client communicator (2); The determination value according to the first received signal strength and the second received signal strength is calculated, and the one or more processors compare the determination value with a reference range to determine the master communicator (5 ) Determining whether the communication with the client communication device (2) is normal or illegal, and if the communication between the master communication device (5) and the client communication device (2) is illegal, the one or more The processor comprises prohibiting unlocking of the vehicle (1) and / or outputting an alert.

One or more implementation examples of the present invention include a master communicator (5) that transmits a query (Srq) using a first radio wave (24) and a response (Sid) that responds to the query (Srq) as a second radio wave (28). A client communication device (2) that transmits data in the same frequency band performs two-way wireless communication to unlock the vehicle (1). The method is such that one or more processors provided in the master communicator (5) and / or the client communicator (2) receive the client communicator (2) from the master communicator (5). Calculating the first received signal strength which is the received signal strength of the first radio wave (24), and the client communicator (2) sets the first received signal strength (30) to the second radio wave (28). Transmitting to the master communicator (5), a second received signal strength that is a received signal strength of the second radio wave (28) received by the master communicator (5) from the client communicator (2); One or more processors calculating, the one or more processors calculating a determination value according to the first received signal strength and the second received signal strength, the one or more processors. The processor compares the determination value with a reference range to determine whether communication between the master communication device (5) and the client communication device (2) is normal or illegal, and the master communication device (5 ) And the client communicator (2), the one or more processors may prohibit the unlocking of the vehicle (1) and / or output an alert.

In one or more implementations of the invention, the master communicator (5) is a key verification device mounted on the vehicle (1) and the client communicator (2) is a portable electronic key.
In one or more implementations of the invention, the master communicator (5) includes a plurality of antennas (12a, 12b) participating in transmission of the first radio wave (24) and reception of the second radio wave (28). A switching unit (12c) for selecting one of the plurality of antennas, and each time the one or more processors receive the response (Sid) a predetermined number of times, the master communicator It is configured to switch the plurality of antennas by controlling the switching unit (12c) of (5).

In one or more implementations of the invention, the master communicator (5) includes a single antenna (12a) participating in transmission of the first radio wave (24) and reception of the second radio wave (28); A switching unit (12c) connected to the single antenna (12a), and each time the one or more processors receive the response (Sid) a predetermined number of times, the master communicator (5) The switching unit (12c) is controlled to switch the directivity of the single antenna (12a).

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the technical concept thereof. For example, some of the parts described in the embodiment (or one or more aspects thereof) may be omitted, or some parts may be combined. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Electronic key (communication terminal, 1st communication part), 3 ... Key operation free system, 4 ... Engine switch, 5 ... Key collation apparatus, 6 ... Door lock apparatus, 7 ... Engine starter, 8 ... In-vehicle bus, 9 ... verification ECU (communication master, second communication unit), 9a ... received signal strength calculation unit (second received signal strength calculation unit), 9b ... calculation unit (calculation unit), 9c ... comparison unit (second) (Comparison means), 11 ... LF transmitter, 12 ... UHF transceiver, 13 ... key control unit, 13a ... comparison unit (first comparison means), 14 ... LF receiver, 15 ... UHF transceiver, 16 ... wake signal, 17, 19 ... Acknowledgment signal, 18 ... Vehicle ID, 20 ... Challenge, 21 ... Response, 22 ... Repeater, 23 ... Communication fraud establishment prevention system, 24 ... UHF radio wave, 25 ... Transmission processor (second transmission execution means) , 26 ... Signal strength calculator (first received signal strength calculator), 27... Received signal strength notifier (first transmission execution unit), 28... UHF radio wave, 29... Main data, 30... Received signal strength information, 31. Determination unit (communication correctness determination means), Srq: request signal as inquiry, Sid: ID signal as response, RSSI1: first received signal strength, RSSI2: second received signal strength.

Claims (9)

1. A first communication unit including a first transmission execution unit; and a second communication unit including a second transmission execution unit. The first transmission execution unit and the second transmission execution unit are bidirectional in the same frequency band. A wireless communication correctness determination system capable of performing radio wave communication,
   The first communication unit includes a first received signal strength calculating unit that calculates a first received signal strength that is a received signal strength of a radio wave from the second communication unit, and the first communication unit includes the first received signal strength calculating unit via the first transmission executing unit. 1 Send information of received signal strength,
   The second communication unit is
   Second received signal strength calculating means for calculating a second received signal strength that is a received signal strength of a radio wave from the first communication unit;
   Calculating means for calculating a determination value based on the first received signal strength and the second received signal strength;
   A wireless communication correctness determination system comprising: communication correctness determination means for determining whether communication with the first communication unit is normal communication based on a comparison result between the determination value and a reference range.
2. 2. The wireless communication correctness determination system according to claim 1, wherein the calculating means calculates a difference between the first received signal strength and the second received signal strength as the determination value.
3. 2. The wireless communication correctness determination system according to claim 1, wherein the calculation unit calculates a degree of coincidence between a time change in the first received signal strength and a time change in the second received signal strength as the determination value.
4. A plurality of antennas connected to at least one of the first communication unit and the second communication unit and used for bidirectional communication between the first communication unit and the second communication unit;
   The wireless communication correctness determination system according to claim 3, further comprising: a switching unit that switches an antenna used for bidirectional communication between the plurality of antennas during bidirectional communication.
5. An antenna connected to at least one of the first communication unit and the second communication unit and used for bidirectional communication between the first communication unit and the second communication unit;
   The wireless communication correctness determination system according to claim 3, further comprising: a switching unit that switches the directivity of an antenna used for bidirectional communication during bidirectional communication.
6. 6. The communication correctness determination unit according to any one of claims 1 to 5, wherein the communication correctness determination unit determines that the communication is not a normal communication when a comparison result between the determination value and the reference range indicates that the communication is not a normal communication a plurality of times. The wireless communication correctness determination system according to claim 1.
7. The first communication unit includes a first comparison unit that compares the first received signal strength with a first threshold value for detecting a received signal strength saturation, and the first received signal strength exceeds the first threshold value. The first transmission execution unit transmits a first attenuation request to the second communication unit;
   The second transmission execution means transmits a radio wave to the first communication unit by performing power control based on the first attenuation request so that a transmission output is attenuated from a previous output,
   The calculation means attenuates the transmission output and transmits a radio wave, and then transmits from the first communication unit, the second received signal strength of the radio wave without the first attenuation request, and the second received signal strength. The wireless communication correctness determination system according to any one of claims 1 to 6, wherein the determination value is calculated based on a new first received signal intensity notified by the calculated radio wave.
8. The second communication unit includes a second comparing unit that compares the second received signal strength with a second threshold value for detecting a received signal strength saturation, and the second received signal strength exceeds the second threshold value. The second transmission execution means transmits a second attenuation request to the first communication unit;
   The first transmission execution means transmits a radio wave to the second communication unit by performing power control based on the second attenuation request so that a transmission output is attenuated from a previous output,
   The calculating means transmits a second second received signal strength of a radio wave that is transmitted from the first communication unit after transmitting the second attenuation request and does not require the second attenuation request, and the new second reception. The wireless communication correctness determination system according to any one of claims 1 to 7, wherein the determination value is calculated based on a first received signal strength notified by a radio wave whose signal strength is calculated.
9. A first communication unit including a first transmission execution unit; and a second communication unit including a second transmission execution unit. The first transmission execution unit and the second transmission execution unit are bidirectional in the same frequency band. A wireless communication correctness determination system capable of performing radio wave communication,
   The first communication unit includes a first received signal strength calculating unit that calculates a first received signal strength that is a received signal strength of a radio wave from the second communication unit. 1 Send information of received signal strength,
   The second communication unit is
   Second received signal strength calculating means for calculating a second received signal strength that is a received signal strength of a radio wave from the first communication unit;
   Calculating means for calculating a determination value indicating a degree of coincidence between the time change of the first received signal strength and the time change of the second received signal strength;
   Communication correct / incorrect determination means for determining whether communication with the first communication unit is regular communication based on a comparison result between the determination value and a reference range,
   The first received signal strength calculating means calculates a first received signal strength associated with a reception time every time a radio wave from the second communication unit is received;
   The said 1st communication part is a radio | wireless communication correctness determination system which transmits the information of the 1st received signal strength of several reception opportunities collectively via the said 1st transmission execution means.

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