JP3416280B2 - Non-contact IC card system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless IC card system used in toll collection facilities on toll roads and the like. [0002] In a conventional toll road toll collection system, a toll collector collects cash directly from a user at a toll booth or collects a toll by letting the user put cash into an automatic machine. The method of letting it be adopted. On the other hand, as a toll collection system that does not require the delivery of tolls at toll gates, a non-contact IC card system that records ID data and uses an in-vehicle device such as a non-contact IC card capable of wireless communication with the outside Is being developed. FIG. 3 is a configuration diagram of a toll road toll collection facility using the above-mentioned non-contact IC card system. As shown in FIG. 1, a vehicle 2 traveling on a road surface 1 is equipped with an on-vehicle device 3. On the other hand, a vehicle detecting device 4 is provided on the road surface 1.
Are arranged. The vehicle detection device 4 includes vehicle separators 5 and 6 disposed on both sides of the road surface 1 and an axis number detector 7 embedded in the road surface 1. The vehicle detection device 4 includes:
The vehicle separators 5 and 6 separate and detect the passing vehicles 2 for each vehicle. At the same time, the number of axes of the vehicle 2 is detected by the number-of-axes detector 7 and a detection signal is transmitted to the toll collection device 8. On the side of the road surface 1, a road machine 9 is installed behind the vehicle detection device 4. The roadside device 9 is provided with a card antenna 10 for receiving a radio wave from the vehicle-mounted device 3. The road device 9 reads the ID data and the balance data transmitted from the on-vehicle device 3 and outputs the data to the toll collection device 8. The toll collection device 8 includes a booth collection device 11 and a receipt issuing device 12 that process data such as a charge amount of the vehicle 2. By pressing a push button of a vehicle type provided in the booth collection device 11. A receipt is issued from the receipt issuing machine 12. [0005] The toll collection device 8 is connected to a data processing device 13. This data processing device 13
Collects and records the processing data of the on-vehicle device 3, the data processed by the booth collection device 11, and the like. In addition, a charge indicator 14 disposed next to the charge collection device 8 displays the charge amount of the vehicle 2 processed by the booth collection device 11, and displays the balance of the prepaid card used in the vehicle-mounted device 3 after use. , The remaining number of times is displayed. In addition, the start guide signal light 15 provided behind the fee display 14 is provided for the vehicle 2 on which the vehicle-mounted device 3 is mounted.
A start warning light 16 is provided at the upper part of the start warning light 16 for notifying a warning when the IC card is read improperly. Further, the start detecting device 17 provided behind the start guide signal light 15 and on the road surface 1
The system is composed of vehicle separators 18 and 19 for detecting the passage of the vehicle and an axis number detector 20 for detecting the number of axes of the vehicle 2. The system detects the completion of the start of the passing vehicle 2 and returns the system to the original state. The surveillance television camera 21 installed behind the start detection device 17 takes an image of the vehicle 2 when the reading of the IC card is poor. FIG. 4 shows a configuration of a conventional detachable on-vehicle device 3. As shown in FIG.
1 and an IC to be inserted into and removed from the adapter 31
And a card 32. Further, the adapter 31
PU (central processing unit) 33, ROM 34, communication circuit 3
5, an antenna 36, an IC card I / F (interface) circuit 37, an IC card insertion section 38, and a battery 39, which are fixedly installed on the vehicle 2. ROM3
4 is a control program, vehicle type data and vehicle ID.
Data is stored, and balance data, payment history data, and the like are stored in the IC card 32 in a rewritable manner. In a normal state, the IC card 32 is inserted into the IC card insertion section 38. IC card 3 inserted
Transfer of data between the CPU 2 and the CPU 33 is performed by the IC card I.
This is performed via the / F circuit 37. And the CPU 33
Performs the following control according to the control program stored in the ROM 34. Power is supplied to each unit by a battery 39, and data is wirelessly transmitted to and from the roadside device 9 by an antenna 36.
The IC card 32 is removed from the adapter 31 when the balance is updated, etc., and after updating the balance, the IC card 32
It is inserted into the C card insertion part 38. As shown in FIG. 3, when the vehicle 2 passes through the vehicle detecting device 4 and enters the toll booth, the vehicle detecting device 4 detects the passing of the vehicle 2 and the detection signal is transmitted to the toll collecting device 8.
Sent to Thereby, the toll collection device 8 starts communication with the on-vehicle device 3 mounted on the vehicle 2 via the on-road device 9. The CPU 33 in the on-vehicle device 3 performs wireless communication with the road device 9 via the communication circuit 35 and the antenna 36, and upon request from the road device 9, balance data and payment history data read from the IC card 32, and ROM
The vehicle type data and the vehicle ID data obtained from 34 are wirelessly output via a communication circuit 35 and an antenna 36. Next, the roadside device 9 receives the ID data and the like from the in-vehicle device 3 and sends it to the toll collection device 8, and transmits to the in-vehicle device 3 charging data corresponding to the vehicle type and the like determined in the toll collection device 8. . The CPU 33 stores the charging data received via the antenna 36 and the communication circuit 35 as a charging history in the IC card 32, and stores the balance obtained by subtracting the charging fee from the previous balance in the IC card 32. FIG. 5 is a block diagram showing a circuit configuration of the ground unit including the road unit 9 and the toll collection device 8 and the like. The ground machine includes a CPU 40, a communication circuit 41, an oscillator 42, a modulator 43, amplifiers 44 and 47, a homodyne detection circuit 55, and the like. The CPU 40 determines a call signal for the passing vehicle 2 and data of a billing signal including billing data corresponding to the vehicle type. The communication circuit 41 includes a CPU 40
Has the function of processing the data obtained from the data into a form capable of wireless communication (creating a packet format) and converting the serial data obtained by wireless communication into a form recognizable by the CPU 40 (disassembling the packet format). I have. The oscillator 42 oscillates a signal having a carrier frequency for wireless communication and inputs the signal to the modulator 43. The modulator 43 modulates the carrier with the transmission data sent from the communication circuit 41, amplifies the modulated wave with the amplifier 44, and radiates the modulated wave from the transmission antenna 10A. When receiving response data from the on-vehicle device 3, the transmitting antenna 10A emits an unmodulated radio wave, that is, only a carrier wave. The in-vehicle device 3 transmits the transmission data to the ground device by using the radio wave. Such a wireless communication system is called a reflection type, and the radio wave is called a reflection radio wave. A reflected radio wave from the on-vehicle device 3 is received by a receiving antenna 10B. The reflected radio wave received by the receiving antenna 10B is amplified by the amplifier 47, and
Distributed to the grid. These two systems are called an I phase and a Q phase, respectively. In the reflection type, a homodyne detection circuit 55 utilizing the I phase and the Q phase is generally used. The homodyne detection circuit 55 includes a distributor 4
8 and 90 ° shifters 49, mixers 50 and 51, low-pass filters 52 and 53, and a signal selection circuit 54.
The homodyne detection has an advantage that the configuration is simple, the frequency of the radio wave can be easily shifted to the baseband, and the reflected radio wave can be detected without being influenced by the transmission radio wave. On the other hand, there are drawbacks such as null point and polarity reversal. This will be described with reference to FIG. FIG. 6 shows a result obtained by multiplying a reflected wave and a carrier by a mixer. In the positional relationship between the antenna of the in-vehicle device and the ground device, a point where the phase relationship exactly coincides is set as 0 ° and used as a reference. The multiplied waveform at this point is W1. When this is signal-processed by a low-pass filter, a waveform indicated by a broken line is obtained. This is the case where data 1 is transmitted. However, at 90 ° and 270 °, data 1 disappears. This is the null point. At 180 °, data 1 is inverted. This is polarity reversal. IQ homodyne detection is effective in resolving null points. That is, the I phase has a phase relationship of 90 °.
In this case, the Q phase should be 180 °, because the null point can be avoided by selecting the one where the signal is observed, that is, by selecting the one with the larger signal. The signal selection circuit 54 shown in FIG.
The magnitude relationship between the phase and the Q phase is compared.
Output to The signal selection circuit 54 is a so-called signal switching circuit, and must switch each time the positional relationship between the on-vehicle unit and the ground unit changes. Specifically, the wavelength at the frequency of 2.45 GHz is 12 cm, and the magnitude relation is switched at P1, P2, P3, and P4 as shown in FIG. However, in the conventional device configured as described above, a data error occurs during the switching time due to the characteristics of the signal selection circuit 54 on the electronic circuit. FIG. 7 illustrates this state. A is transmission data of the on-vehicle device 3 and is data used by the ground device. B is I-phase detection data, and C is Q-phase detection data. Here, it is assumed that the magnitude relationship between the signals B and C is reversed from the time T3 to T4. Therefore, for the signal D output from the signal selection circuit 54, B data should be selected until T3, and C data should be selected from T4. However, in practice, the switching time of the signal selection circuit 54 occurs at T4, and unstable data at which neither is selected appears at T4. The present invention has been made in order to solve the above-mentioned problems, and it is intended to transmit data from a vehicle-mounted device to a ground device and to generate a data error occurring when switching between two signals after homodyne detection. It is an object of the present invention to provide a contactless IC card system having a function of correcting an error. [0023] The present invention provides a communication means and
Adapter with data processing means and this adapter
It can be inserted and removed, and balance data and payment history data are
Performs wireless communication with the vehicle unit and the earth located a Ground Vehicles consisting IC card stored in the non-contact IC card system which detects the received signal by homodyne detection on the ground machine, of the vehicle device adapter to transmit to the ground machine by adding error correction bits to the transmission data is provided an error correction encoding circuit, out of the homodyne detection circuit in the ground Vehicles
An error correction decoding circuit is provided on the input side, and after receiving transmission data from the in-vehicle device and performing homodyne detection, decoding is performed by using the correction bits by the error correction decoding circuit , and the error correction is performed. The decoding circuit converts the data bits
Data buffer to store and decoding to store correction bits
Circuit and the data stored in the data buffer.
Compare the correction bits stored in the
If there is an error in the data,
It consists of an inspection circuit that corrects and reproduces normal data.
It is characterized by . When the vehicle enters a communicable range with a ground unit provided at, for example, a toll gate, communication starts between the vehicle-mounted unit and the ground unit mounted on the vehicle. The in-vehicle device adds an error correction code to transmission data such as balance data read from the IC card by an error correction code circuit, and wirelessly outputs the data through a communication circuit and an antenna. The ground unit receives the data sent from the in-vehicle unit with the receiving antenna,
After amplification by an amplifier, homodyne detection is performed and output to an error correction decoding circuit. This error correction decoding circuit compares the data and the correction bit with respect to the homodyne-detected signal to obtain a correlation, and when the data is erroneous, corrects the error with the correction bit to reproduce normal data. . Therefore, even if a data error occurs at the time of signal switching after homodyne detection, correct data can be restored by the error correction decoding circuit 70, and wireless communication between the onboard unit and the ground unit can be performed correctly. . Embodiments of the present invention will be described below with reference to the accompanying drawings. The toll road toll collection facility in the embodiment described below is shown in FIG.
Is the same as that shown in FIG. FIG. 1 shows a non-contact I according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of an in-vehicle device 3 in the C card system. As shown in FIG. 1A, the on-vehicle device 3 includes an adapter 31 fixedly installed on the vehicle 2 and a plug-in / pull-out of the adapter 31 and rewritably stored balance data and payment history data. Portable IC card 3
2. The adapter 31 includes a CPU 33, a ROM
34, error correction code circuit 60, communication circuit 35, antenna 36, IC card I / F circuit 37, IC card insertion unit 3
8. It comprises a battery 39. The ROM 34 stores a control program, vehicle type data, and vehicle ID data. The error correction code circuit 60 is constructed as shown in FIG.
The data buffer 61 and the correction encoding circuit 62
And a selector 63. Data buffer 6
1 stores transmission data from the CPU 33 and outputs the data to the selector 63. The correction encoding circuit 62 generates data having a correlation with the transmission data stored in the data buffer 61 and outputs the data to the selector 63. Selector 63
Switches between the content stored in the data buffer 61 and the data obtained by the correction encoding circuit 62 on a bit-by-bit basis and outputs the data to the communication circuit 35. Therefore, the data sent to the communication circuit 35 is added with one correction bit obtained by the correction encoding circuit 62 for one bit of data. FIG. 2 shows a non-contact type I according to an embodiment of the present invention.
It is a block diagram showing composition of a ground machine in a C card system. This ground machine is characterized in that an error correction decoding circuit 70 is added after the signal selection circuit 54 to the conventional circuit shown in FIG. The error correction decoding circuit 70 shown in FIG.
As shown in (1), it comprises a data buffer 71, a decoding circuit 72 and an inspection circuit 73. The data bits of the data output from the signal selection circuit 54 are
In the data buffer 71 of FIG.
Is stored in As described above, since the data bits and the correction bits are alternately included in the transmission data, such processing can be easily realized. The inspection circuit 73 compares the data with the correction bit to obtain a correlation. If the data has an error, the error is compensated by the correction bit, and the data is passed even if the correction bit is in error. , Normal data reproduction can be performed. Next, a data communication operation between the on-board unit 3 and the ground unit in the above embodiment will be described. In FIG. 1, the IC card 32 is usually in a state of being inserted into the IC card insertion section 38. In this state, as shown in FIG. 3, when the vehicle 2 passes through the vehicle detection device 4 and enters the tollgate, the vehicle detection device 4 detects the passage of the vehicle 2 and sends a detection signal to the toll collection device 8. Can be Thereby, the toll collection device 8 starts communication with the on-vehicle device 3 mounted on the vehicle 2 via the on-road device 9. The CPU 33 of the on-vehicle device 3 performs wireless communication with the road device 9 via the communication circuit 35 and the antenna 36, and upon request from the road device 9, balance data and payment history data read from the IC card 32, and ROM
The vehicle type data and the vehicle ID data obtained from 34 are wirelessly output via a communication circuit 35 and an antenna 36. In-vehicle device 3
Adds an error correction code to the data output from the CPU 33 by the error correction code circuit 60 when transmitting data to the roadside device 9. That is, the error correction code circuit 60 is configured as shown in FIG.
The transmission data from the CPU 33 is stored in the data buffer 61 as shown in FIG. Further, the correction encoding circuit 62 generates data having a correlation with the transmission data stored in the data buffer 61 and outputs the data to the selector 63. The selector 63 switches the contents stored in the data buffer 61 and the data obtained by the correction encoding circuit 62 for each bit and outputs the data to the communication circuit 35. That is, the selector 63 adds one correction bit obtained by the correction encoding circuit 62 to the data stored in the data buffer 61 for each data bit, and outputs the result to the communication circuit 35. It is transmitted to the on-road unit 9. The on-road unit 9 receives the ID data and the like from the on-vehicle unit 3 and sends it to the toll collection unit 8 for processing. As shown in FIG. 2, the ground unit including the road unit 9 and the toll collection device 8 receives the reflected radio wave from the on-vehicle unit 3 through a receiving antenna 10.
After receiving the signal at B and amplifying it at the amplifier 47, the signal is homodyne detected by the homodyne detection circuit 55 and output to the error correction decoding circuit 70. The error correction decoding circuit 70 stores the data bits of the data output from the homodyne detection circuit 55 in the data buffer 71 and the correction bits in the decoding circuit 72, as shown in FIG. 2B. A check circuit 73 compares the data stored in the data buffer 71 and the decoding circuit 72 with the correction bit to obtain a correlation. If the data is erroneous, the error is supplemented with the correction bit to correct the error. The data is reproduced and output to the CPU 40 in FIG. The CPU 40 determines a call signal for the passing vehicle 2 and data of a billing signal including billing data corresponding to the vehicle type, processes the data into a form that can be wirelessly communicated by the communication circuit 41, and processes the data into the modulator 43. input.
The modulator 43 modulates a carrier generated by the oscillator 42 with transmission data sent from the communication circuit 41, amplifies the modulated wave by the amplifier 44, and radiates the modulated wave from the transmission antenna 10A to the vehicle-mounted device 3. The CPU 33 in the vehicle-mounted device 3 stores the billing data received via the antenna 36 and the communication circuit 35 as a billing history in the IC card 32, and subtracts the balance obtained by subtracting the billing fee from the previous balance into the IC card. 32. As described above, in the signal selection circuit 54 in the homodyne detection circuit 55 of the ground unit, even if a data error occurs at the time of signal switching, the error correction decoding circuit 7
With 0, the correct data can be restored, and the wireless communication between the on-board unit 3 and the ground unit can be correctly performed. As described above in detail, according to the present invention, an error correction code circuit is provided in an adapter of a vehicle-mounted unit to add an error correction code to transmission data. An error correction decoding circuit is provided on the output side to perform error correction, so that even if a data error occurs when switching signals in the signal selection circuit in the homodyne detection circuit, correct data can be restored, and Wireless communication with the device can be performed correctly. Therefore, even if the phase relationship between the onboard unit and the ground unit changes due to the running of the vehicle,
Data errors are eliminated, and a great effect can be exerted particularly in the case of handling the amount of money such as toll collection.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a vehicle-mounted device in a non-contact IC card system according to one embodiment of the present invention. FIG. 2 is a configuration diagram of a ground machine in the embodiment. FIG. 3 is a configuration diagram of a toll road toll collection facility using a non-contact type IC card. FIG. 4 is a configuration diagram of a vehicle-mounted device in a conventional contactless IC card system. FIG. 5 is a configuration diagram of a ground machine in a conventional contactless IC card system. FIG. 6 is a principle diagram of IQ homodyne detection. FIG. 7 is an explanatory diagram of a data error that occurs when a signal selection circuit is switched in a homodyne detection circuit. [Description of Signs] 2 Vehicle 3 In-vehicle device 8 Toll collection device 9 Roadside device 31 Adapter 32 IC card 33 CPU 35 Communication circuit 37 IC card I / F circuit 38 IC card insertion unit 40 CPU 41 Communication circuit 44, 47 Amplifier 48 Distribution Device 49 90 ° shifter 50, 51 mixer 52, 53 low-pass filter 54 signal selection circuit 55 homodyne detection circuit 60 error correction coding circuit 61 data buffer 62 correction coding circuit 63 selector 70 error correction decoding circuit 71 data buffer 72 decoding circuit 73 Inspection circuit

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI H03M 13/00 H04L 1/00 B H04B 7/26 27/22 Z H04L 1/00 H04B 7/26 E (56) References Special JP-A-6-6261 (JP, A) JP-A-7-66747 (JP, A) JP-A-5-159143 (JP, A) JP-A-2-183389 (JP, A) JP-A-63-44293 ( JP, A) JP-A-3-37570 (JP, U) Patent 3105647 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 27/00 G06K 17/00 G07B 15/00 501 H03M 13/00 H04L 1/00

Claims (1)

(57) [Claims] [Claim 1] An antenna provided with communication means and data processing means.
The adapter and the adapter can be inserted and removed so that the balance
From an IC card that stores data and payment history data
Comprising vehicle device and performs wireless communication with the earth the installed Ground Vehicles, in the non-contact IC card system which detects the received signal by homodyne detection on the ground machine, error correction encoding circuit in the vehicle-mounted device of the adapter And send error correction bits to the transmission data and transmit it to the ground equipment.
The ground unit is provided with an error correction decoding circuit on the output side of the homodyne detection circuit, and after receiving transmission data from the on-vehicle unit and performing homodyne detection, decoding is performed by using the correction bits by the error correction decoding circuit. Characterized by the front
The error correction decoding circuit is used to store data bits.
A buffer, a decoding circuit for storing the correction bits,
Data stored in data buffer and stored in decoding circuit
The corrected bits are compared to determine the correlation, and the data
If the data is
A contactless IC card system comprising: an inspection circuit for reproducing data .