KR20000047447A - Dsrc car-mounted equipment - Google Patents

Abstract

PURPOSE: A DSRC(dedicated short-range communication) loader for a vehicle is provided to promptly operate the data processing of a received signal regardless of the difference in the transmission frequencies from an on-road unit. CONSTITUTION: A logical sum of the output signal of a transmission circuit and a field intensity discrimination signal consists a logical circuit in order to generate a logical signal. A controller establishes a frequency of a local oscillator as a first frequency and monitors a logic signal for a certain time in response to a field intensity discrimination signal. If the logical signal displays an H level, the frequency of the local oscillator is switched to a second frequency. Therefore, a prompt data processing of the received signal is capable of operating regardless of the difference in the transmission frequencies from an on-road unit.

Description

DSRC Car Mounting Equipment {DSRC CAR-MOUNTED EQUIPMENT}

The present invention is a Dedicated Short-Range Communication (hereinafter abbreviated as "DSRC") used in an Intelligent Traneport System (hereinafter, referred to as ITS) such as an ETC (Road Automatic Charge Receiving System). With respect to the vehicle onboard device, especially when a transmission signal of a certain level or more is received from the hearth, it is possible to promptly process the data of the signal in spite of the difference in the transmission frequency, and the reception circuit starts automatically only when necessary. This invention relates to a DSRC vehicle mounter which suppresses power consumption.

In general, in a DSRC vehicle mounting apparatus used for ITS, a reception circuit is always activated during driving of a vehicle so that narrow-band communication can be reliably enabled when the vehicle enters the narrow-band communication area and a communication request with the hearth is made.

For example, in the case of the narrow-line communication target of the ETC hearth, a large number of communication frequencies are used in correspondence with several gates of the toll road entrance and reception, so that the narrow-band communication target can receive a plurality of transmission frequencies from the hearth. A local transmitter is inserted into the new circuit to switch the reception frequency at regular intervals.

6 is a block diagram schematically showing a conventional DSRC vehicle mounting device, in FIG. 6, 1 is a roadbed installed in a driving path of a vehicle, and 2 is a DSRC vehicle mounting device for performing narrow communication with the roadbed 1 (hereinafter, FIG. Simply referred to as "vehicle mounting".

The vehicle mounting device 2 is composed of the following elements 3-10.

3 is a reception antenna for receiving the transmission signal W1 from the hearth 1, 5 is a reception circuit for receiving the reception signal A from the reception antenna 3 through the reception mixer 4.

6 denotes a low pass filter (hereinafter abbreviated as "LPF") which removes high frequency components from the transmission signal to the hearth 1, 8 represents the transmission signal B as a transmission signal W2 through the mixer 7; Transmission antenna to transmit to.

9 is a local transmitter for converting the local frequencies input to the reception mixer 4 and the transmission mixer 7 into first and second frequencies f1 and f2.

10 denotes a controller for controlling the vehicle-mounted vehicle 2, which controls the selected frequency of the local generator 9 by the control signal C, transmits / receives to / from the hearth 1, and outputs the reception circuit 5. Data processing is performed in accordance with the signal, and transmission control of the transmission signal B is performed through the LPF 6 and the transmission mixer 7.

In Fig. 6, the reception mixer 4, the reception circuit 5, the local transmission 9, and the controller 10 in the on-board machine 2 are always fed and in the activated state, and remain in a receivable state.

Next, the frequency selection operation in the receiving circuit 5 in the on-board machine 2 for receiving the transmission signal W1 from the hearth 1 will be described.

First, the controller 10 in the on-board machine 2 always changes the control signal C for the local generator 9 in a period of an arbitrary time cycle t while the vehicle is running.

As a result, the selection frequency of the local generator 9 is alternately switched to the first and second frequencies f1 and f2 at a constant time cycle t.

The time cycle t at this time is set to about twice the time corresponding to the length of one data group included in the reception signal A, and frequency information recorded at the head of one data group can be reliably read within the time cycle t. There is.

Therefore, the transmission signal W1 from the hearth 1 is reliably received through the reception mixer 4 within the time cycle t without being dependent on the difference in the transmission frequency, and is input to the controller 10 as the reception signal A.

The controller 10 recognizes the frequency information in the one data group included in the received signal A, and then locks the control signal C for the local transmitter 9 at the time when the received signal A is received.

At this time, the reception signal A is demodulated through the reception mixer 4 and the reception circuit 5 and input to the controller 10.

In this way, after the frequency selection is completed, the controller 10 performs a series of data processing of the reception data processing and the transmission signal B after the frequency selection.

The conventional DSRC vehicle mounter switches the control signal C at a constant time cycle t as described above, acquires the received signal A, and completes the frequency selection operation after recognizing the frequency information in one data group. The time until at least (period of time cycle t) has a problem in that the reception frequency cannot be set.

In addition, since the controller 10 cannot select a frequency during a predetermined time cycle t, when the vehicle is traveling at high speed, the vehicle deviates from the narrow communication area before recognizing the frequency information of the received signal A, thereby communicating. There was a problem that could cause an error.

In addition, in order to maintain the reception standby state of the on-vehicle vehicle 2, since the power supply of the reception mixer 4, the reception circuit 5, the local transmitter 9, and the controller 10 is always activated, the current consumption is large. As a result, the load of the on-vehicle battery is increased, resulting in a short battery life and a periphery of the receiving circuit 5 to generate heat.

In particular, since the vehicle mounting apparatus 2 is mounted on a dashboard structure in a vehicle compartment, it is accompanied by an increase in temperature due to solar radiation, and thus is generally in a strict temperature environment exceeding 100 ° C. Fever is a big problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to obtain a DSRC vehicle mounter which enables data processing of a received signal promptly, regardless of the difference in transmission frequency from the hearth.

In addition, an object of the present invention is to obtain a DSRC vehicle mounter which enables data processing of a received signal quickly and automatically activates a receiving circuit only when necessary to reduce power consumption.

The DSRC vehicle mounting apparatus according to claim 1 of the present invention includes a reception antenna for receiving a transmission signal from a hearth installed on a driving path of a vehicle, a reception circuit for receiving a reception signal from the reception antenna, and a reception mixer. It owns a local transmitter which converts the input local frequency into the first and second frequencies, and a controller which controls the selected frequency of the local transmitter and performs data processing in accordance with the output signal of the receiver circuit. In the DSRC vehicle mounting apparatus for communication, a comparator for demodulating a received signal from a receiving antenna, an electric field strength judging circuit for generating an electric field strength judging signal when the developed intensity of the received signal through the comparator is higher than a predetermined value; It has a logic circuit that generates a logical signal by taking the logic between the output signal of the receiving circuit and the electric field strength determination signal. The controller sets the frequency of the local transmitter in advance to the first frequency, monitors the logical signal over a predetermined time in response to the electric field strength determination signal, and if the logical signal indicates the H level, monitors the frequency of the local transmitter. When the frequency is fixed at the first frequency and the logical signal indicates the L level, the frequency of the local generator is switched to the second frequency.

In addition, the DSRC vehicle mounting apparatus according to claim 2 of the present invention includes a power supply circuit having a first power supply for always feeding and a second power supply for selectively feeding power, and the controller and the electric field strength determining circuit of claim 1 Powered by one power supply, the reception mixer, receiver circuit, local transmitter and logical circuit are supplied by the second power supply, and the controller outputs a control signal for starting the second power supply to the power supply circuit in response to the electric field strength determination signal. It is.

In addition, the DSRC vehicle mounting apparatus according to claim 3 of the present invention includes a power supply circuit according to claim 1, having a first power supply for constant power supply and a second power supply for selectively supplying power in response to the electric field strength determination signal. The determination circuit is powered by the first power supply, and the controller, the reception mixer, the reception circuit local transmitter and the logical circuit are supplied by the second power supply.

1 is a block diagram showing Embodiment 1 of the present invention.

Fig. 2 is a flowchart showing the operation of Embodiment 1 of the present invention.

3 is a block diagram showing Embodiment 2 of the present invention;

4 is a flowchart showing the operation of the second embodiment of the present invention;

5 is a block diagram showing Embodiment 3 of the present invention.

Figure 6 is a block diagram showing a conventional DSRC vehicle mounting.

<Description of the symbols for the main parts of the drawings>

1.Street top, 2A ~ 2C. DSRC vehicle loading machine,

3. receiving antenna, 4. receiving mixer,

5. receiving circuit, 9. local transmitter,

10A ~ 10C. Controller, 11.detection diode,

12. Field strength determination circuit, 13. Logical circuit,

20,20C. Power circuit, 21. primary power,

22. Second power source, A. received signal,

A5. Output signal of receiving circuit, C, F. Control signal,

D. Field strength determination signal, E. Logical signal,

W1. Transmission Signal,

Embodiment 1

EMBODIMENT OF THE INVENTION Hereinafter, Embodiment 1 of this invention is described with reference to drawings.

FIG. 1 is a block diagram showing Embodiment 1 of the present invention, and FIG. 2 is a flowchart showing the operation of the controller in FIG.

In Fig. 1, the same elements as those described above (see Fig. 6) are denoted by the same reference numerals, and detailed description thereof is omitted.

In addition, 24 and 10A correspond to the vehicle mounting apparatus 2 and the controller 10 which were mentioned above, respectively.

In addition to the above-described configuration, the vehicle-mounted device 2A determines the electric field strength of the detection diode 11 for demodulating the reception signal A from the reception antenna 3 and the reception signal A through the detection diode 11 to determine the electric field strength. The electric field strength determination circuit 12 which outputs the signal D, and the logical circuit 13 which outputs the logical signal E by taking the logic of the output signal A5 of the receiving circuit 5 and the electric field intensity determination signal D are provided.

The electric field strength determination circuit 12 outputs the electric field strength determination signal D when the electric field strength of the reception signal A is equal to or higher than a predetermined value.

The electric field strength determination signal D and the logical signal E are input to the controller 10A.

Next, the frequency selection operation according to Embodiment 1 of the present invention shown in FIG. 1 will be described with reference to the flowchart of FIG. 2.

First, the controller 10A control signal C is fixed while the vehicle is running, and the selected frequency of the local transmitter 9 is set in advance to the first frequency f1 (either of two kinds of frequencies f1 and f2), and the reception standby state is maintained. (Step S1). At this time, it is assumed that the transmission signal W1 from the hearth 1 is transmitted at a frequency of either the first frequency f1 or the second frequency f2, and the controller 10 selects the first frequency f1. Control signal C is output.

Here, when the transmission signal W1 from the hearth 1 is received by the reception antenna 3, the reception signal A is input to the reception mixer 4 and is simultaneously input to the electric field strength determination circuit 12 through the detection diode 11. Is entered.

At this time, the reception signal A is input to the electric field strength determination circuit 12 regardless of the transmission frequency from the hearth 1, but for the reception circuit 5, demodulation data is generated only when the transmission frequency is the first frequency. Obtained.

The logical circuit 13 inputs to the logical signal E controller 10A for the logic of the electric field strength determination signal D from the electric field strength determination circuit 12 and the output signal A5 of the reception circuit 5.

The controller 10A determines whether or not the electric field strength determination signal D is on in the reception standby state (step S2). If the electric field strength determination signal D is determined to be off (i.e. NO), the reception standby state (step S1) is continued.

On the other hand, if it is judged in step S2 that the electric field strength determination CD is turned on (main YES), since the reception signal A of the electric field strength of a predetermined value or more is acquired, the controller 10A responds to the electric strength determination signal D, thereby providing a logical signal. E is monitored over a period of time to determine whether or not the logical signal E is on (step S3). At this time, the controller 10A triggers the electric field strength determination signal D to assure the determination of the logical signal E, detects the rising (or falling) edge of the logical signal E over a predetermined time, and the logical signal E is a fixed time. Monitor the display of On (H level) or Off (L level) in succession.

If it is determined that the logical signal E indicates ON (H level) (i.e., YES), the selected frequency (first frequency) of the local generator 9 is set to a frequency corresponding to the transmission frequency of the hearth (1). Therefore, the control signal C is kept as it is (fixed at the first frequency).

As a result, the controller 10A picks up the output signal A5 of the reception circuit 5 that has passed through the logic circuit 13 after frequency selection and demodulates the reception signal A according to the output signal A5, which not only processes the received data but also the transmission signal. A series of data processing of B is executed (step S4). Return to step S1.

On the other hand, if it is determined in step S3 that the logical signal E displays off (i.e., NO), the selected frequency (first frequency) of the local generator 9 does not match the transmission frequency of the hearth 1. Since the control signal C is not changed, the selected frequency of the local generator 9 is switched to the second frequency (step S5). Subsequently, it is determined whether or not the logical signal E indicates on (H level) as in step S3 (step S6). If it is determined that the logical signal E is on (i.e., YES), the selected frequency of the local generator 9 is fixed to the second frequency, and a series of data processing after the frequency switching control is performed (step S4). On the other hand, if it is determined in step S6 that the logical signal E is off (i.e., NO), since the frequency of the received signal A is neither of the first and second frequencies, it returns without executing the data processing step S4.

In addition, the logical signal E indicates a state in which the transmission frequency of the hearth 1 is down-converted to a desired IF frequency by the selected frequency of the controller 10A, and the controller 10A shows the state of the electric field strength determination signal D. The rising timing is triggered to determine the frequency of the frequency by monitoring the time edge of 3 bits or more of the signal rate of the logical signal E.

In general, in the DSRC protocol used for the communication between the hearth 1 and the vehicle-mounted device 2A, some encoding (such as Manchester type false encoding) is performed on a transmission / reception signal.

For example, when Manchester coding is performed on the transmission signal W1, the first frequency f1 assuming that the on-board device 2A can downconvert to a desired IF frequency coincides with the transmission frequency of the hearth (1). If so, the level of the logic signal A is not fixed over a period of 3 bits or more.

Therefore, when downconverted to the desired IF frequency, the logical signal E is always predicted while the time corresponding to 3 bits has elapsed from the input time of the electric field strength determination signal D.

In this case, the controller 10A monitors the level of the logical signal E for a time equivalent to 3 bits or more, and when the edge input (level number) of the logical signal E is confirmed, the received data processing (step) without changing the control signal C. S4) is executed.

Further, if there is no edge input of the logical signal E and the level fixed state is confirmed over a time equivalent to 3 bits or more, the controller 10A changes the control signal C for the local generator 9, thereby selecting the selected frequency. After switching, a series of data processing of transmission and reception is performed.

Here, the case where the transmission frequency from the hearth 1 is changed to two types has been described. However, even when the transmission frequency is changed to three or more types, the frequency change processing step as in step S5 is repeated, so The frequency can be switched to easily handle.

In this way, by monitoring the edge of the logical signal E with the electric field strength determination signal D as a trigger, frequency selection in narrow-band communication can be performed at high speed.

Therefore, even when the vehicle is traveling at high speed, the hearth 1 and the vehicle mounting apparatus 2A can communicate with each other without expanding the communication area.

Embodiment 2

In the first embodiment, the reception circuit 5 is always started without considering waste of power consumption, but the reception circuit 5 may be started only when necessary.

An embodiment 2 of the present invention, in which the receiving circuit 5 is activated only when necessary, will be described with reference to the drawings.

FIG. 3 is a block diagram showing Embodiment 2 of the present invention, FIG. 4 is a flowchart showing the operation of the controller of FIG. 3, and in FIG. 3, 2B and 10B are the vehicle mounting apparatus described above (see FIG. 1). Corresponding to 2A) and the controller 10A, respectively, the same reference numerals are given to the above-described ones, and the above description is omitted.

In addition to the above-described configuration, the on-vehicle vehicle 2B includes a power supply circuit 20 driven under the control of the controller 10B, and the power supply circuit 20 includes a first power supply 21 for constant power feeding, and It has a 2nd power supply 22 which supplies electric power.

The controller 10B outputs a control signal F for activating the second power supply 22 to the power supply circuit 20 in response to the electric field strength determination signal D. FIG.

In this case, the controller 10B and the electric field strength determination circuit 12 are fed from the first power source 21 and are always started.

On the other hand, the reception mixer 4, the reception circuit 5, the local generator 9 and the logic circuit 13 are powered by the second power supply 22, and are activated only when the control signal F is generated.

As shown in Fig. 3, the electric power of the electric field strength determination circuit 12 and the controller 10B is constituted by the first power supply 21, and the reception mixer 4, the reception circuit 5, the local transmitter 9, and The power supply of the logical circuit 13 is constituted by the second power supply 22.

Next, the frequency selection operation according to Embodiment 2 of the present invention shown in FIG. 3 will be described with reference to the flowchart of FIG.

In FIG. 4, S1 to S6 are the same steps as described above, and thus are not described herein.

First, since the control signal F is not output in the initial state, the second power supply 22 remains off, and circuit elements such as the receiving circuit 5 other than the controller 10B and the electric field strength determining circuit 21 are It is not activated.

As a result, the current consumption in the reception standby state of the transmission signal W1 from the hearth 1 is suppressed.

Next, when it is determined in step S2 that the electric field strength determination signal D indicates on (i.e., YES), the controller 10B outputs the control signal F with the electric field strength determination signal D as a trigger, and the second power source ( 22) is started (step S11). At this time, the controller 10B checks the electric field strength of the desired level or more by the edge of the electric field strength determination signal D, and then outputs the control signal F to the power supply circuit 20.

In this way, the second power supply 22 is turned on to start the reception mixer 4, the reception circuit 5, the local transmitter 9, and the logical circuit 13, and then proceeds to step S3.

As described above, after performing frequency selection and transmission / reception processing in steps S3 to S6, the second power supply 22 is turned off again (step S12) and returned.

In this way, the first power source 21 of the power supply circuit 20 drives only the controller 10B and the electric field strength determination circuit 12 in the reception standby state, and the second power source 22 responds to the control signal F to receive the reception mixer. (4) The reception circuit 5, local transmitter 9 and logical circuit 13 are driven only when necessary.

When the transmission signal W1 from the hearth 1 is terminated and the electric field strength of the reception signal A is equal to or less than a predetermined value, the controller 10B checks the off state of the electric field strength determination signal D, and the power supply circuit 20 The control signal F for turning off the second power supply 22 is output.

In this way, the power consumption of the vehicle-mounted device 2B is reduced by turning off the power of the reception mixer 4, the reception circuit 5, the local transmitter 9, and the logic circuit 13 in the weight of the reception standby apparatus. At the same time, the life of the vehicle-mounted battery can be reduced by reducing the load.

Embodiment 3

In the second embodiment, the controller 10B is always started by the power supply from the first power source, but may be started only when necessary by the power supply from the second power source 22.

EMBODIMENT OF THE INVENTION Hereinafter, Embodiment 3 of this invention which makes a controller start only when needed is demonstrated according to drawing.

Fig. 5 is a block diagram showing Embodiment 3 of the present invention, in which like reference numerals are used to omit the above description.

In Fig. 5, 2C, 10C, and 20C correspond to the vehicle mounting apparatus 2B, the controller 10B, and the power supply circuit 20 described above (see Fig. 3), respectively.

In this case, the power supply circuit 20C uses the electric field strength determination signal D as a control signal, and starts the second power supply 21 in response to the electric field strength determination signal D. FIG.

In Fig. 5, the electric field strength determination circuit 12 is supplied from the first power source 21 and is activated even in the reception standby period.

On the other hand, the reception mixer 4, the reception circuit 5, the local transmitter 9, the controller 10C and the logic circuit 13 are fed from the second power supply 22, and only when the electric field strength determination signal D is turned on. Is fed.

In this manner, normally, only the electric field strength determining circuit 12 is started, and the second power source 22 is started only when the electric field strength determining signal D is turned on by the reception signal A of a predetermined level or higher, and the other circuit is activated. Since the power consumption of the controller 10C in the air can be reduced, the current consumption can be suppressed again.

As described above, according to claim 1 of the present invention, a reception antenna for receiving a transmission signal from a hearth provided on a driving path of a vehicle, a reception circuit for receiving a reception signal from a reception antenna, and a reception mixer. Owns a controller which controls the selected frequency of the local transmitter for converting the input local frequency into the first and second frequencies, and performs data processing according to the output signal of the receiving circuit, and performs narrow-band communication with the above. In a DSRC vehicle mounting apparatus, a detection diode for demodulating a reception signal from a reception antenna, an electric field strength determination circuit for generating an electric field strength determination signal when the electric field strength of the reception signal through the detection diode is higher than a predetermined value, and an output of the reception circuit. And a logic circuit that takes a logic of the signal and the electric field strength determination signal and generates a logical signal. The frequency of the local transmitter is set to the first frequency in advance, the logical signal is monitored over a predetermined time in response to the electric field strength determination signal, and when the logical signal indicates the H level, the frequency of the local transmitter is determined as the first frequency. When the logical signal indicates the L level, the frequency of the local transmitter is switched to the second frequency, so that the data processing of the received signal can be processed quickly, regardless of the difference in the transmission frequency from the hearth. There is an effect that a DSRC onboard is obtained.

According to claim 2 of the present invention, in claim 1, there is provided a power supply circuit having a first power supply for always feeding and a second power supply for selectively feeding power, and the controller and the electric field strength determining circuit are connected to the first power supply. Power supply by the second power supply, and the controller is configured to output the control signal for starting the second power supply to the power supply circuit in response to the electric field strength determination signal. It is possible to obtain a DRSC vehicle mounter which enables data processing of a received signal as soon as possible and at the same time automatically activates a receiving circuit only when necessary to reduce power consumption.

According to claim 3 of the present invention, in claim 1, the power supply circuit includes a power supply circuit having a first power supply for constant power supply and a second power supply for selectively supplying power in response to the electric field strength determination signal, and according to the electric field strength determination circuit. Since the power is supplied by the first power supply, and the controller, the reception mixer, the reception circuit, the local transmitter and the logical circuit are supplied by the second power supply, the DSRC vehicle onboard device which further reduces power consumption can be obtained.

Claims (3)

A first and second reception antennas for receiving a transmission signal from a hearth installed on a driving path of a vehicle, a reception circuit for receiving a reception signal from the reception antenna, and a local frequency input to the reception mixer; DSRC vehicle for owning a local transmitter for switching to the frequency of 2 and a controller for controlling the selected frequency of the local transmitter and performing data processing according to the output signal of the receiving circuit, and for performing narrow-band communication with the hearth. A field strength determination circuit for demodulating a reception signal from the reception antenna by the payloader and an electric field strength determination signal when the field strength of the reception signal through the detection diode is equal to or greater than a predetermined value, and an output signal of the reception circuit; And a logical circuit which takes a logic with the field strength determination signal and generates a logical signal. The controller sets the frequency of the local transmitter to a first frequency in advance, monitors the logical signal over a predetermined time in response to the electric field strength determination signal, and outputs the H signal to the H level. And the frequency of the local transmitter is fixed to the first frequency, and when the logical signal indicates an L level, the frequency of the local transmitter is switched to a second frequency. The method of claim 1, A power supply circuit having a first power supply for always feeding and a second power supply for selectively feeding power, wherein the controller and the electric field strength determining circuit are supplied by the first power supply, and the receiving mixer, the receiving circuit, The local generator and the logical circuit are powered by the second power supply, and the controller outputs a control signal for starting the second power supply to the power supply circuit in response to the electric field strength determination signal. DSRC vehicle loading. The method of claim 1, And a power supply circuit having a first power supply for always feeding power and a second power supply for selectively feeding power in response to the electric field strength determination signal, wherein the electric field strength determination circuit is supplied from the first power supply, the controller, And the receiving mixer, the receiving circuit, the local transmitter, and the logical circuit are fed by the second power source.