JP2008311728A - Narrow area communication system, on-vehicle narrow area communication unit, transmitter and mobile receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a narrow area communication system in which a transmitter transmits information stably even if the direction of a communication object changes relatively, and a mobile can receive information while localizing the communication object exactly. <P>SOLUTION: Information is received from the rear of a vehicle C1 by applying an antenna of narrow directivity characteristics. Information is transmitted from the front of the vehicle C1 by applying an antenna of wide directivity characteristics. The existing direction of information transmission vehicles C3-C4 in the rear of the vehicle C1 can be recognized. Measurements of the field strength is utilized for recognizing the distance of the information transmission vehicles C3-C4 in the rear of the vehicle C1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a narrowband communication system, a narrowband communication vehicle-mounted device, a transmitter, and a mobile receiver using DSRC (Dedicated Short Range Communication) technology.

In the DSRC technology, an ETC system is currently used as a narrow-area communication system using the 5.8 GHz band for improving convenience in automobile traffic. In recent years, applications to automatic toll collection systems such as gas stations, parking lots, and highways, and next-generation VICS (registered trademark) systems have been studied. This type of communication technology has been widely studied as a mobile communication technology between vehicles (for example, see Patent Document 1). According to the technique disclosed in Patent Document 1, a plurality of communication modules are provided around a vehicle, and information can be exchanged between limited vehicles.
JP 2005-117427 A

  For example, in a system that supports driving using a variety of information obtained by narrow area communication, it is necessary to know the position of a communication target when instructing a direction to avoid an approaching obstacle. However, in the conventional short-range communication technology, when a wide directivity is set, if there are a plurality of communicable devices in the effective communication range, the transmitted information is transmitted from a device in any direction within the communication range. There is a problem that it is difficult to determine whether the information is correct. On the other hand, when the directivity is narrowed, when the moving body moves, the distance and direction with respect to the communication target change relatively, so that even if the transmitter transmits information, the information cannot be accurately transmitted. There was a fear.

  The present invention has been made in view of the above circumstances, and its purpose is to enable a transmitter to stably transmit information even when the direction of a communication target changes relatively, and to transmit information from a communication target. Is to provide a narrow area communication system that can be used in association with a physical position, and a narrow area communication vehicle-mounted device, a transmitter, and a mobile receiver used in the system.

  According to the first aspect of the present invention, since the transmitter transmits a radio signal at a horizontal directivity angle of the first angle level wider than the second angle level, information is transmitted to a wider range of communication targets. Thus, even if the direction of the communication target changes relatively, information can be stably transmitted. Moreover, since the mobile receiver receives a radio signal at a horizontal directivity angle of the second angle level that is narrower than the first angle level, the mobile receiver is narrowed down from a communication target. Information can be received. As a result, the mobile receiver can determine the direction of the communication target, and use the information from the physical position in association with the physical position.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The vehicle C is equipped with a narrow area communication vehicle-mounted device (DSRC vehicle-mounted device) 1. In the vehicle, the narrow area communication vehicle-mounted device 1 includes one antenna unit at each of a front portion and a rear portion of the vehicle C. The narrow area communication vehicle-mounted device 1 is configured by combining so-called antenna separation type units.

  FIG. 1 schematically shows an electrical configuration block of a narrow-range communication vehicle-mounted device. FIG. 2 schematically shows the form of the antenna installed in the vehicle and its directivity, and schematically shows the form of communication between the vehicles.

  As shown in FIG. 1, the narrow-area communication vehicle-mounted device 1 includes a transmitter 2 and a receiver 3 for wireless communication, and is configured to process data by a data processing unit A. The transmitter 2 includes a data transmission unit 4 and a transmission antenna 5 for transmitting a radio signal, and the data transmission unit 4 modulates the data and transmits the data to the front of the vehicle through the transmission antenna 5 by the radio signal. (See FIG. 2 for the transmission direction). The narrow-range communication vehicle-mounted device 1 is equipped with a display device, a speaker (sound output device), and the like (not shown).

  The radio signal modulation data may be information including the type and attribute of the vehicle in which the transmitter 2 is mounted (classification category information or vehicle type information such as general vehicles and emergency vehicles), vehicle speed information, Vehicle operation information such as accelerator opening information, brake operation amount information, and steering angle information may be included. In addition, as information added to these, for example, in the case of information transmitted by an ambulance (emergency vehicle), it includes route schedule information and route opening request information indicating “straight route opening request because sick person is being transported” and the like. May be.

  The transmission antenna 5 is an antenna having transmission directivity of a predetermined first angle (for example, the first angle θ1 in the horizontal direction in front of the vehicle) in the horizontal plane, and has a wide directivity characteristic with respect to the front of the vehicle. Installed. Therefore, the data transmission unit 4 can transmit a radio signal over a wider range in front of the vehicle.

  The receiver 3 includes a data receiving unit 7 having a demodulation function for receiving and demodulating a radio wave signal through the receiving antenna 6. The receiver 3 can also have a function of measuring the electric field strength of the received signal and measuring the distance from the narrow-range communication vehicle-mounted device 1 mounted on another vehicle from the measurement result. The reception antenna 6 is configured by an antenna having reception directivity characteristics of a predetermined second angle θ2 (narrower than the first angle θ1) in a horizontal plane.

  In addition, although embodiment which provided the receiving antenna 6 so that it may become a high directivity characteristic in the range of a predetermined 2nd angle (theta) 2 is shown, the technique which changes an antenna directivity using an adaptive array antenna in this case is shown. It may be applied, or the direction of high directivity may be changed by applying a high directivity antenna and mechanically scanning and controlling the direction of the directivity antenna.

The operation of the above configuration will be described.
In the present embodiment, an embodiment is shown in which the transmitter 2 radiates a radio signal in the forward direction of the vehicle through the transmission antenna 5 and the receiver 3 receives the radio signal from the rear of the vehicle by the reception antenna 6.

  FIG. 2 shows a form in which the narrow area communication system of the present invention is applied to a communication system between an emergency vehicle and a general vehicle. This communication system S includes a plurality of narrow-area communication vehicle-mounted devices 1 mounted on general vehicles C1 to C3 and emergency vehicle C4. The following description shows the operation as the operation of the vehicle-mounted device 1, but indicates the processing performed by the data processing unit A of the vehicle-mounted device 1 unless otherwise specified.

  As shown in FIG. 2, the narrow-range communication vehicle-mounted device 1 mounted on the general vehicle (own vehicle) C <b> 1 transmits a radio signal via the transmission antenna 5 in a wide range in front of the general vehicle C <b> 1 via the transmission antenna 5. Radiate. The general vehicle C2 is traveling in front of the traveling lane of the general vehicle C1. Although this general vehicle C2 is also equipped with the narrow-range communication vehicle-mounted device 1, the narrow-range communication vehicle-mounted device 1 receives a radio wave signal transmitted from the rear of the vehicle by the receiving antenna 6. The transmission antenna 5 is installed, for example, in the vicinity of a room mirror in the vehicle interior and transmits within a wide directivity angle θ1. The receiving antenna 6 is installed at the rear end of the vehicle, for example, and can scan and receive within a narrow directivity angle θ2 at the rear of the vehicle.

  In this case, since the horizontal plane directivity T of the transmission antenna 5 of the vehicle C1 covers a wide range, even if the vehicle C2 is traveling in another lane, the narrow area communication vehicle-mounted device 1 of the vehicle C2 stabilizes transmission information from the vehicle C1. Can be received.

  Moreover, the narrow area communication vehicle-mounted device 1 mounted on the general vehicle C1 receives a radio wave signal from the rear side of the general vehicle C1 via the reception antenna 6. The following vehicle C3 located immediately after the vehicle C1 is also equipped with the narrow-band communication vehicle-mounted device 1, and the narrow-band communication vehicle-mounted device 1 transmits a radio signal through the transmission antenna 5 over a wide range in front of the vehicle C3. To do. An emergency vehicle C4 is traveling in a lane adjacent to the traveling lane of the vehicle C1. The emergency vehicle C4 also includes the on-board communication device 1 and transmits the radio signal via the transmission antenna 5 over a wide area in front of the vehicle C4.

  In this case, the narrow area communication vehicle-mounted device 1 of the general vehicle C1 scans and receives the rear of the vehicle C1 in the horizontal direction. Then, when the receiver 3 of the narrow area communication vehicle-mounted device 1 scans a lane side different from the traveling lane of the general vehicle C1, the transmission information of the emergency vehicle C4 can be received. Conversely, when the receiver 3 of the narrow-range communication vehicle-mounted device 1 of the general vehicle C1 scans the same lane as the travel lane of the general vehicle C1, the general vehicle C3 located immediately after the general vehicle C1 Send information can be received. That is, since the narrow area communication vehicle-mounted device 1 of the general vehicle C1 recognizes the reception scanning direction when receiving the information, the information received by the receiving antenna 6 and the actual position (direction) of the communication target vehicle are determined. Can be easily tied.

  When information including the type and attribute of the vehicle (classification category information or vehicle type information such as general vehicle and emergency vehicle) is included in the transmission information of the transmitter 2, the type and attribute of the communication target vehicle, the degree of urgency, etc. Can be recognized, and this information can be notified to the driver.

  When information including vehicle speed information, accelerator opening information, brake operation amount information and steering wheel steering angle information is included in the transmission information of the transmitter 2, the traveling state of the communication target vehicle (the traveling state) ), Danger level, urgency level, etc. can be recognized, and this information can be notified to the driver.

  When the route schedule information and the route opening request information of the emergency vehicle C4 are included in the transmission information of the transmitter 2, the future traveling direction and request of the communication target vehicle can be recognized. The driver can be notified.

  The transmitters 2 of the vehicles C1 to C4 radiate radio signals in the forward direction of the vehicles, and the receiver 3 of the vehicle C1 receives radio signals radiated in front of the vehicles C3 and C4 from the rear of the vehicle C1. The transmission direction of the information transmitted from the rear of the vehicle C1 can be determined.

  When the receiver 3 has a function of measuring the electric field strength of the received signal and measuring the distance from the on-vehicle communication device 1 mounted on the other vehicle based on the measurement result, from the other vehicles C2 to C4 The transmission position of the transmission information can be determined. Therefore, warning information such as “Please avoid while approaching” can be notified to the driver.

  Moreover, you may make it transmit the information which the narrow area communication vehicle equipment 1 of the vehicle C1 received as it is toward the front. Then, when the vehicles C1 to C4 are connected, information can be continuously transmitted from the rear to the front, and information can be transmitted promptly in an emergency.

(Second Embodiment)
FIG. 3 shows a second embodiment of the present invention. The difference from the previous embodiment is that information is transmitted to the rear of the vehicle and received from the front of the vehicle. The same parts as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. Only different parts will be described below.

FIG. 3 schematically shows a communication state between the vehicle and the obstacle.
As shown in FIG. 3, an obstacle 10 may be installed on the road surface when road construction is performed. The obstacle 10 is equipped with a transmitter 2 and is configured to transmit a radio signal that has been data-modulated in the direction opposite to the traveling direction. The modulation data may be dimensional information or weight information of the obstacle.

  On the other hand, the narrow-range communication vehicle-mounted device 1 is mounted on the vehicle C1. The narrow area communication vehicle-mounted device 1 is configured such that the receiver 3 receives a radio signal transmitted from the front of the vehicle, and the transmitter 2 is configured to transmit the radio signal to the rear of the vehicle. Then, since the narrow area communication vehicle-mounted device 1 mounted on the vehicle C1 has the configuration described in the above-described embodiment, it is possible to specify the direction and the position of the obstacle 10 existing in the traveling direction. Therefore, the data processing unit A can notify the driver that the obstacle 10 exists by using a display device or a speaker.

(Other embodiments)
The present invention is not limited to the above embodiment, and for example, the following modifications or expansions are possible.
When the traveling speed of the vehicle C1 is relatively slow, the communicable angle is wide and close to the communicable distance, and when the traveling speed is relatively fast, the communicable angle is narrow and the communicable distance is long. Then, it is possible to perform control adapted to the purpose and situation.

The figure which shows schematically the electric constitution of the narrow region communication vehicle equipment which concerns on the 1st Embodiment of this invention. A diagram schematically showing the state of communication between vehicles FIG. 2 equivalent view according to the second embodiment of the present invention.

Explanation of symbols

  In the drawings, 1 is a narrow-area communication vehicle-mounted device, 2 is a transmitter, 3 is a receiver, 5 is a transmission antenna, 6 is a reception antenna, C1 to C4 are vehicles, and S is a narrow-area communication system.

Claims (5)

A transmitter configured to transmit a radio wave signal that is data-modulated over a wide range with the angle of directivity in a horizontal plane as a predetermined first angle;
A mobile receiver configured to receive a radio signal in a narrow range of a second angle that is an angle of directivity in a horizontal plane that is narrower than the first angle of the radio signal transmitted by the transmitter. A narrow-area communication system.   The narrow-area communication system according to claim 1, wherein the transmitter and the mobile receiver are mounted on a vehicle.   A narrow-area communication vehicle-mounted device comprising the transmitter of the narrow-area communication system according to claim 1 or 2 and a mobile receiver.   A transmitter used in the narrow-area communication system according to claim 1 or 2.   A mobile receiver, which is used in the narrow-area communication system according to claim 1 or 2.

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