JP2000298746A - Road side radio equipment receiving electric field intensity measuring system in electric tarrif collection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road side radio equipment received electric field intensity measuring system for surely performing electric tarrif collection by quicky and accurately detecting a traveling vehicle in the gate of a pay road. SOLUTION: This system is provided with road side radio equipment 10, having an antenna 11 for communicating with a passing vehicle, an analog/digital conversion part 12B connected with the antenna for analog/digital converting the measured value of received electric field intensity, and an optical serial communication interface 12A for transmitting the measured value of the received electric field, and an optical transmission path 13 connected with the optical serial communication interface 12A, and a communication controller 14 having an optical serial communication interface 14A connected with the transmission path 13 and a communication control part 14B connected with the serial communication interface 14A. Thus, the measured value of the received electric field intensity is analog/digital converted by the road side radio equipment 10, and the measured value of the received electric field intensity is transmitted to the communication controller 14, by using the optical serial communication interface 12A between the communication controller 14 and the road side radio equipment 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system between a roadside apparatus and a communication control apparatus, and more particularly to a system for measuring a received electric field intensity by a roadside apparatus in an automatic toll collection system (ETC) for a toll road. .

[0002]

2. Description of the Related Art A highway user is expected to operate a vehicle to a destination in a short time by a smooth flow of the vehicle. However, even when using a toll road such as an expressway, it takes time to collect tolls at the expressway gates, causing a problem that caused traffic congestion.
An automatic toll collection system (ETC) for toll roads has been considered.

[0003]

By the way, in order to construct the automatic toll collection system, it is indispensable to detect the traveling vehicle at the gate of the toll road quickly and accurately and to perform the automatic tolling surely. is there. In particular, in seasons such as consecutive holidays and school excursions, it is important to accurately detect vehicles rushing to the gates of toll roads individually and to reliably collect tolls.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a method for measuring the reception field strength of a roadside wireless device in an automatic toll collection that can detect a traveling vehicle at a gate of a toll road quickly and accurately and perform an accurate automatic toll billing. The purpose is to provide a system.

[0005]

Means for Solving the Problems [1] In a receiving electric field strength measuring system by a roadside wireless device in automatic toll collection, an antenna for communicating with a passing vehicle, and a value of the receiving electric field strength measurement connected to the antenna. Analog /
A roadside apparatus having an analog / digital conversion unit for performing digital conversion, a serial communication interface for transmitting the value of the received electric field strength measurement, a data transmission path connected to the serial communication interface, and a connection to the data transmission path A communication control device having a serial communication interface to be connected and a communication control unit connected to the serial communication interface. The roadside wireless device performs analog / digital conversion of the value of the received electric field strength measurement. According to the present invention, the value of the received electric field strength measurement is transmitted to the communication control device by using a serial communication interface with the roadside apparatus.

[2] In the system for measuring the received electric field intensity by the roadside apparatus in the automatic toll collection according to the above [1], the data transmission path is an optical serial communication transmission path.

[3] In the reception electric field strength measurement system by the roadside apparatus in the automatic toll collection according to the above [1], the reception electric field intensity measurement is provided with a plurality of slots,
In this embodiment, the received electric field strengths of a plurality of passing vehicles are individually measured.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an arrangement of a roadside apparatus to which the present invention is applied.

As shown in FIG. 1, a gantry 6 is provided with a roadside wireless device (hereinafter simply referred to as a wireless device) 1, and a communication control device 3 is provided on the ground side. The communication control device 3 and the wireless device 1 are connected by a composite cable 2 for data transmission. Reference numeral 7 denotes a running vehicle.

FIG. 2 is a block diagram of a system for measuring the reception electric field strength of a roadside wireless device in automatic toll collection of the roadside wireless device according to an embodiment of the present invention.

In this figure, reference numeral 10 denotes a wireless device;
Antenna 11 for transmitting and receiving to and from vehicles passing through the gate
And a roadside wireless unit 12. Roadside wireless unit 1
2 includes an optical serial communication interface 12A and an A / D converter 12B for measuring the received electric field strength. Here, the reception electric field strength measurement A / D converter 12B has an error correction conversion table.

A data transmission composite cable (optical transmission line) 13 for performing optical serial communication uses, for example, a plastic clad optical fiber (PFC).

An optical serial communication interface 14 is connected to the optical transmission line 13.
A and a communication control unit [DSRC (ITS short-range communication) protocol management unit] 14B, and are appropriately connected to a higher system, for example, a higher ETC processing device.

FIG. 3 is an explanatory diagram of a system for monitoring and controlling a wireless device by optical serial data transmission according to an embodiment of the present invention.

The wireless device 10 and the communication control device 14 are connected by a composite cable 13 for data transmission. As the composite cable 13 for data transmission, for example, a plastic clad optical fiber (PCF) × 6 cores + two metal wires are used.

Therefore, the transmission data (TXD) 21, the transmission clock (TXC) 22, and the control signal 23 transmitted from the communication control device 14 to the radio device 10 are stored in the plastic clad optical fiber (PCF) × 6 cores. Have.
The reception data (RXD) 24 and the reception clock (RXC) 2 transmitted from the wireless device 10 to the communication control device 14
5, and a signal line 27, 28 having a monitor signal 26 and transmitted by two metal wires.

The details of these signals are shown in TXD21.
Is RSU transmission data and uses a Manchester code of 1.024 Mbps. TXC22 is an RSU transmission clock, and uses 1.024 MHz. RXD24 is R
This is SU reception data and uses an NRZ signal of 1.024 Mbps. RXC25 is an RSU reception reproduction clock, and uses 1.024 MHz. The control signal 23 is a wireless device control signal, and uses an NRZ signal of 1.024 Mbps. The monitoring signal 26 is a wireless device monitoring signal,
An NRZ signal of 1.024 Mbps is used. Signal line 2
Signals of the power supply alarm non-voltage contact are transmitted to 7, 28.

FIG. 4 is a diagram showing a format of a control / monitoring signal of a wireless device by optical serial data transmission according to an embodiment of the present invention.

As shown in this figure, the control signal (communication control device → wireless device) 23 is a synchronization flag (4 bits) 23
A + control command (12 bits) 23B + parity P2
It is composed of 3C + timing flag (3 bits) 23D.

On the other hand, the monitor signal 26 indicates the synchronization flag (4b
(it) 26A + monitoring signal (12 bits) 26B + parity P26C.

Next, the details of the control command (transmission direction: communication control device → wireless device) will be described. (1) Connection: always transmitted when communication control is initialized.

Check the rise of the wireless device.

The wireless device transmits "RDY" and the operating state as monitoring data. (2) Status notification: The operating status in the wireless device is transmitted as monitoring data.

The health of the wireless device is checked by transmitting it periodically. (3) RSSI: A of RSSI (received field strength measurement)
/ D conversion is performed.

The converted value is transmitted as monitoring data.

This RSSI process is a feature of the present invention, and will be described later in detail. (4) Transmission stop: After receiving the timing flag, the transmission is stopped at the next clock (TXWoff). (5) Transmission start: After receiving the timing flag, transmission is started (TXWon) at the next clock. (6) Disconnect: Communication control resets "disconnect command"
To the wireless device.

After receiving the command, the wireless device immediately stops transmitting and does not accept the command until the "connection command" is received. (7) Return mode activation: Return mode activation instruction in wireless device logic unit (8) Return mode release: Return mode release instruction in wireless device logic unit (9) ASK monitoring activation: AS in wireless device logic unit
K monitoring function activation instruction (10) ASK monitoring stop: A in the wireless device logic unit
SK monitoring function stop instruction (11) Frequency setting: Frequency setting and change instruction (12) Electronic Vol: Electronic volume change (13) TX-ATT: Transmission variable attenuator setting value (14) RX-ATT: Receive variable attenuator Set Value FIG. 5 is a diagram showing a procedure for measuring the reception field strength of the roadside apparatus by optical serial data transmission according to the embodiment of the present invention.

As shown in this figure, the communication control device 14 sets an FCM (frame control message) [message from the road side to the vehicle side] (step S3).
1) Then, in the communication control device 14, when a "request for RSSI (reception field strength measurement)" is performed from slot 1 (step S32) (step S33), A / D conversion is performed in the wireless device 10 (step S33). S34), "RSSI
The “value” is transmitted from the wireless device 10 to the communication control device 14 (step S35). For example, an RSSI process having a function of determining a distance for performing communication with a first vehicle traveling in a tollgate booth is performed.

Also, in slot n (step S36), as in slot 1, when an "RSSI (electric field strength measurement) request" is made (step S37), A / D conversion is performed in radio device 10. (Step S38),
The “RSSI value” is transmitted from the wireless device 10 to the communication control device 14 (Step S39). For example, an RSSI process having a function of determining a distance for performing communication with an n-th vehicle traveling in a tollgate booth is performed.

As described above, it is possible to measure the received electric field strength between each vehicle passing through each slot and to determine whether or not processing such as automatic billing is possible.

FIG. 6 is an explanatory diagram of the RSSI (field strength measurement) sampling timing showing the embodiment of the present invention.

FIG. 6A is a time chart of a transmission clock (TXC), FIG. 6B is a time chart of a UWIN (unique word window), FIG. 6C is a time chart of a control signal, and FIG. (D) AD TRIG
(Trigger of A / D converter), FIG. 6
(E) is a time chart of the monitoring signal.

As shown in these figures, the control data 35
Is followed by a parity check (odd number bits), then a timing flag (3 bits) is set, the timing is set, a trigger signal 36 for the A / D converter is generated, and a monitor signal A synchronization flag (4 bits) is set at the beginning, and the RSSI data 37 is transmitted.

As described above, the value of the RSSI is A / D-converted by the wireless device 10, and the RSI value is converted using the optical serial communication interface 12 A between the communication control device 14 and the wireless device 10.
The value of the SSI is transmitted to the communication control device 14.

The timing of A / D conversion is also controlled by communication through the optical serial communication interface 12A.

With this configuration, even when an ETC-compatible vehicle and a non-ETC-compatible vehicle enter the toll booth continuously, the RSSI value can be accurately grasped.
Automatic toll collection can be performed reliably without mistaking ETC-compatible vehicles and non-compliant vehicles.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0039]

As described above, according to the present invention, the following effects can be obtained.

(1) According to the first aspect of the present invention, an antenna for communicating with a passing vehicle, and an analog / digital converter connected to the antenna and for converting the measured value of the received electric field strength from analog to digital. A roadside apparatus having a serial communication interface for transmitting the value of the received electric field strength measurement, a data transmission path connected to the serial communication interface, a serial communication interface connected to the data transmission path, A communication control unit having a communication control unit connected to the serial communication interface, wherein the wireless device performs analog-to-digital conversion of the value of the received electric field strength measurement, and establishes a serial communication interface between the communication control device and the wireless device. To transmit the value of the received electric field strength measurement to the communication control device. So fast the road-to-vehicle, it is possible to perform an accurate reception field strength measurement.

(2) According to the second aspect of the present invention, since the data transmission line is an optical serial communication transmission line, the quality of transmission can be improved and the communication specification can be easily changed.

(3) According to the third aspect of the present invention, the reception electric field strength measurement is provided with a plurality of slots, and the individual reception electric field strength measurements of a plurality of passing vehicles are performed.
By associating the number of slots with the number of passing vehicles, the value of RSSI can be accurately grasped, and automatic toll collection is ensured without mistaking ETC-compatible vehicles and non-compliant vehicles. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an arrangement of a roadside apparatus to which the present invention is applied.

FIG. 2 is a block diagram of a roadside apparatus reception electric field strength measurement system in automatic toll collection of the roadside apparatus according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a wireless device monitoring / control system using optical serial data transmission according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a format of a control / monitoring signal of a wireless device by optical serial data transmission according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a procedure for measuring the reception field strength of the roadside apparatus by optical serial data transmission according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram of an RSSI (field strength measurement) sampling timing showing the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1, 1 wireless device 2 composite cable for data transmission 3, 14 communication control device 6 gantry 7 vehicle 11 antenna 12 roadside wireless unit 12A optical serial communication interface 12B A / D converter for receiving electric field strength measurement 13 data for optical serial communication Transmission composite cable (optical transmission line) 14A Optical serial communication interface 14B Communication control unit [DSRC protocol management unit] 21 Transmission data (TXD) 22 Transmission clock (TXC) 23 Control signal 23A, 26A Synchronization flag (4 bits) 23B Control command (12 bits) 23C Parity P 23D Timing flag (3 bits) 24 Received data (RXD) 25 Receive clock (RXC) 26 Monitor signal 26B Monitor signal (12 bits) 26C Parity P 27, 28 Signal line (metal wiring 2) Book) 35 control data 36 A / D converter trigger signal 37 RSSI data

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Claims (3)

[Claims] In a system for measuring a received electric field strength by a roadside apparatus in automatic toll collection, (a) an antenna for communicating with a passing vehicle, and an analog / digital value of the received electric field strength measured connected to the antenna. A roadside apparatus having an analog / digital converter for converting, a serial communication interface for transmitting the value of the received electric field strength measurement, (b) a data transmission path connected to the serial communication interface, and (c) a data transmission path connected to the serial communication interface. A communication control device having a serial communication interface connected to the data transmission path and a communication control unit connected to the serial communication interface; and (d) converting the value of the received electric field strength measurement by the Digital conversion, and a serial communication interface between the communication control device and the roadside apparatus. A roadside wireless device reception electric field strength measurement system in automatic toll collection, wherein the value of the reception electric field strength measurement is transmitted to the communication control device using a base station. 2. The system for measuring the received electric field intensity by a roadside apparatus in automatic toll collection according to claim 1,
The said transmission line is an optical serial communication transmission line, The roadside apparatus reception electric field strength measuring system characterized by the above-mentioned. 3. The system for measuring the received electric field intensity by a roadside apparatus in automatic toll collection according to claim 1,
The reception field strength measurement system for automatic toll collection, wherein the reception field strength measurement is provided with a plurality of slots and individually measures the reception field strength of a plurality of passing vehicles.