DSRC car-mounted equipment

• US 6,356,207 B1
• Filed: 08/17/2000
• Issued: 03/12/2002
• Est. Priority Date: 04/03/2000
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Oouchi, Jun
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): GOINS, DAVETTA WOODS
• Application Number:
  US09/640,376
• Time in Patent Office: 572 Days
• Field of Search: 340/928, 340/933, 340/942, 340/825.39, 340/902, 340/10.3, 340/906, 701/32, 701/36, 701/117, 455/99, 455/105, 455/107, 455/447, 455/446, 235/384
• US Class Current: 340/928
• CPC Class Codes: H04B 17/15 Performance testing
• CPC Class Codes: H04B 17/17 Detection of non-compliance or faulty performance, e.g. response deviations H04B17/18 takes precedence
• CPC Class Codes: H04B 17/19 Self-testing arrangements
• CPC Class Codes: H04B 17/23 Indication means, e.g. displays, alarms, audible means
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/354 Adjacent channel leakage power

Abstract

A DSRC car-mounted equipment which self-diagnoses its communication function and informs the driver of the result, comprising a first local oscillator 30 for generating a car-mounted equipment frequency fosc, a demodulator 16 for detecting the electric field intensity HE and for picking up reception data D1, a car-mounted controller 40 for fetching the reception data by changing over the transmission/reception change-over switch SW1 and for sending transmission data D2, a second local oscillator 31 that outputs a frequency for detecting abnormal condition corresponding to an on-the-road equipment frequency fs, and means for judging the condition of the transmission/reception circuit using the frequency for judging abnormal condition, wherein the transmission/reception change-over switch is connected to the reception circuit, abnormal condition is judged from at least either the electric field intensity or the reception data detected based on a leakage power of the frequency for detecting abnormal condition, and information output means 50 is driven.

Claims

1. A DSRC car-mounted equipment comprising:

a transmission/reception antenna for executing communication with an on-the-road equipment installed on a road;

a transmission/reception change-over switch for changing over the transmission/reception function of said transmission/reception antenna;

a transmission/reception circuit including a reception circuit and a transmission circuit selectively connected to said transmission/reception antenna via said transmission/reception change-over switch;

a first local oscillator for generating a car-mounted equipment frequency related to said transmission/reception circuit;

a demodulator for detecting the electric field intensity and for picking up reception data from a signal received by said reception circuit;

a car-mounted controller for fetching said reception data by controlling the change-over of said transmission/reception change-over switch, and for sending transmission data to said transmission circuit;

an information output means connected to said car-mounted controller; and

a second local oscillator that outputs, to said transmission circuit, a frequency for detecting abnormal condition corresponding to an on-the-road equipment frequency transmitted from said on-the-road equipment;

wherein

said car-mounted controller includes an abnormal circuit judging means for judging the condition of said transmission/reception circuit by using said frequency for detecting abnormal condition; and

said abnormal circuit judging means judges said transmission/reception circuit to be abnormal and drives said information output means when at least either the electric field intensity or the reception data detected based upon a leakage power of said frequency for detecting abnormal condition is not satisfying a predetermined condition in a state where said transmission/reception change-over switch is connected to said reception circuit.

2. A DSRC car-mounted equipment according to claim 1, further comprising an abnormal condition detector switch which selectively connects said first or the second local oscillator to said transmission circuit;

wherein

said second local oscillator outputs a frequency equal to said on-the-road equipment frequency as said frequency for detecting abnormal condition; and

said abnormal circuit judging means judges the condition of said transmission/reception circuit by comparing the electric field intensity detected based on a leakage power of said frequency for detecting abnormal condition with a predetermined value in a state where said abnormal condition detector switch is connected to said second local oscillator side.

3. A DSRC car-mounted equipment according to claim 2, wherein said abnormal condition detector switch is connected to said second oscillator when the power source circuit is closed, said second local oscillator is driven when the power source circuit is closed, and said transmission circuit is turned off when the power source circuit is closed.

4. A DSRC car-mounted equipment according to claim 2, wherein said abnormal circuit judging means sends a predetermined data that has been set in advance to said transmission circuit, and judges the condition of said transmission/reception circuit by comparing the electric field intensity and the reception data with a predetermined value and said predetermined data, said electric field intensity and said reception data being detected based on a leakage power of said frequency for detecting abnormal condition ASK-modified with said predetermined data.

5. A DSRC car-mounted equipment according to claim 1, further comprising:

a mixer for detecting abnormal condition inserted between said first and second local oscillators and said transmission circuit; and

a filter inserted between said mixer and said transmission circuit to permit the passage of said on-the-road equipment frequency and said car-mounted equipment frequency only;

wherein

said second local oscillator is selectively driven and outputs, as said frequency for detecting abnormal condition, an intermediate frequency which is a difference between said on-the-road equipment frequency and said car-mounted equipment frequency; and

said abnormal circuit judging means judges the condition of said transmission/reception circuit by comparing the electric field intensity detected based on a leakage power of said frequency for detecting abnormal condition with a predetermined value when said second local oscillator is driven.

6. A DSRC car-mounted equipment according to claim 5, wherein said second local oscillator is driven when the power source circuit is closed, and said transmission circuit is turned off when the power source circuit is closed.

7. A DSRC car-mounted equipment according to claim 5, wherein said abnormal circuit judging means sends a predetermined data to said transmission circuit, and judges the condition of said transmission/reception circuit by comparing the electric field intensity and the reception data with a predetermined value and said predetermined data, said electric field intensity and said reception data being detected based on a leakage power of said frequency for detecting abnormal condition ASK-modified with said predetermined data.

8. A DSRC car-mounted equipment according to claim 5, wherein said first and second local oscillators include a common reference frequency oscillator for outputting a reference frequency inclusive of said intermediate frequency, said first local oscillator has a frequency multiplier for forming said car-mounted equipment frequency from said reference frequency, and said second local oscillator has a second filter for picking up said intermediate frequency from said reference frequency.

9. A DSRC car-mounted equipment according to claim 1, wherein said information output means includes at least either a buzzer or a display unit to inform the abnormal condition of said transmission/reception circuit by voice or display.

10. A DSRC car-mounted equipment according to claim 1, further comprising an external storage medium connected to said car-mounted controller to transmit and receive data related to the toll collection, wherein said car-mounted controller exchanges the data related to the toll collection between said on-the-road equipment installed on a toll road and said external storage medium, and automatically executes the toll collection processing based on the data related to the toll collection.