JP4682478B2 - Non-contact IC card communication system, IC card and IC card reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-contact type IC card communication system in which an IC card reader and a non-contact type IC card communicate with each other using radio wave signals, an IC card used in the system, and an IC card reader.
[0002]
[Problems to be solved by the invention]
FIG. 6 shows an example when the IC card reader and the non-contact type IC card communicate with each other. For example, the IC card 1 approaches the reader / writer 2 installed on the wall surface of a building, for example, while being held in the hand of the user. For example, the IC card 1 is outside the communication area 3 of the reader / writer 2. Are moved sequentially from position A to position B inside the communication area 3 and from position B to position C closer to the reader / writer 2.
[0003]
The radio wave signal transmitted from the reader / writer 2 to the IC card 1 is, for example, an ASK (Amplitude Shift Keying) modulation signal. In consideration of user convenience, it is preferable to set the communication area 3 of the reader / writer 2 to be as large as possible. Accordingly, the reader / writer 2 also sets the ASK modulation degree and the reception sensitivity using the vicinity of the limit position of the communication area 3 as a reference for adjustment.
[0004]
However, if the IC card 1 is located very close to the reader / writer 2 as in the position C, the IC card 1 itself may affect the high frequency characteristics of the reader / writer 2. Then, even if the reader / writer 2 is adjusted so that the ASK modulation degree becomes 10% in accordance with the vicinity of the limit position of the communication area 3, when the IC card 1 reaches the position C, the resonance frequency of the IC card 1 is reached. As a result, the antenna matching of the reader / writer 2 changes and the level of the ASK modulation signal changes. As a result, the IC card 1 cannot receive the data transmitted by the reader / writer 2 and the IC card 1 cannot be processed normally.
[0005]
Further, when the circuit on the IC card 1 side operates, noise (unwanted radiation) is generated by the operation (see FIG. 7). That is, when the CPU in the IC card 1 operates to read / write data from / to the memory or drive the communication circuit, the current consumption state changes, which is equivalent to a state in which load modulation is performed in a pseudo manner. In communication with the reader / writer 2, noise is generated.
[0006]
When the noise generation level is relatively high, the influence of noise is relatively small near the limit position of the communication area 3, but the influence of noise is relatively large near the position C. Therefore, when the reader / writer 2 receives noise, it may be regarded as response data of the IC card 1, and in this case, there is a problem that original response data cannot be received.
[0007]
As described above, the magnitude of influence when the IC card 1 approaches the reader / writer 2 varies depending on the individual electrical characteristics of each IC card 1. In other words, such a difference in electrical characteristics may exist between manufacturers that produced IC cards, or even IC cards produced by the same manufacturer may exist for each IC card. It has been difficult to make adjustments on the reader / writer 2 side so that any IC card 1 is matched.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to enable adjustment by an IC card reader so that communication can be optimally performed according to the manufacturing conditions of each IC card. It is an object of the present invention to provide a contact IC card communication system, an IC card used in the system, and an IC card reader.
[0009]
[Means for Solving the Problems]
According to the communication system of the contactless IC card according to claim 1, wherein, in the storage means of the IC card, data relating to the IC card specific manufacturing conditions are stored. Then, when there is a data read request from the outside (IC card reader), the IC card reads the data from the storage means and transmits it by a radio signal. When the IC card reader receives the data transmitted from the IC card side, the IC card reader adjusts parameters relating to communication conditions performed with the IC card based on the data.
[0010]
Here, the data related to the manufacturing conditions of the IC card is, for example, the electrical characteristics (for example, the consumption of the IC chip internal circuit) measured by the operator in the IC card manufacturer or model name, or the inspection process at the time of manufacturing. Current value, internal resistance value, resonance frequency of antenna portion, Q value, etc.). Such data is stored in the storage means of the IC card.
[0011]
In other words, when the IC card is very close to the IC card reader, the electrical characteristics of the IC card affect the IC card reader side and change the communication conditions. Therefore, by adjusting parameters related to communication conditions based on IC card data received on the IC card reader side, even if the electrical characteristics of various IC cards are slightly different, the characteristics affect communication. It is possible to reduce the influence and perform communication with each IC card satisfactorily.
When the IC card reader recognizes that there are a plurality of IC cards in its own communication area, it reads data relating to the manufacturing conditions of each IC card and changes the parameters relating to the communication conditions in accordance with the respective data. However, communication is sequentially performed with a plurality of IC cards.
[0012]
According to the non-contact type IC card communication system according to the second aspect, the parameter relating to the communication condition is the modulation degree of the transmission signal. That is, from the data regarding the manufacturing conditions of the IC card, when the IC card approaches the IC card reader side, it is expected that the modulation degree of the transmission signal waveform changes due to the influence of the impedance of the IC card. If the modulation degree of the transmission signal is adjusted so as to reduce those influences, communication with the IC card can be performed satisfactorily.
[0013]
According to the communication system of the non-contact type IC card according to claim 3, the parameter relating to the communication condition is the reception sensitivity of the reception signal. That is, when it is predicted that data related to IC card manufacturing conditions will be received erroneously due to the noise generated by the IC card when the IC card approaches the IC card reader side. If the reception sensitivity of the received signal is adjusted so as to reduce the influence of the signal, communication with the IC card can be performed satisfactorily.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS. A reader / writer (IC card reader) 11 shown in FIG. 1 is connected to a host device (host, not shown) such as a personal computer via a serial interface, for example, and is based on an application program instruction on the host device side. The IC card 12 shown in FIG. 2 is communicated by radio signals.
[0015]
That is, the reader / writer 11 performs polling to intermittently transmit a calling code to the IC card 12 in order to detect that the IC card 12 has approached its own communication area (request). When the user carrying the IC card 12 is located within the communication area, the IC card 12 responds by generating an operation power source and a clock from a signal transmitted by the reader / writer 11.
[0016]
FIG. 1 is a functional block diagram showing an electrical configuration inside the reader / writer 11. A CPU (control circuit) 13 performs serial communication with a host device via a host interface (I / F) unit 14. The reset IC 15 outputs a reset signal for turning the CPU 13 on and off. The encoding unit 16 encodes transmission data given serially from the CPU 13 using, for example, an NRZ (Non Return to Zero) method and outputs the encoded data to the modulation unit 17.
[0017]
The carrier oscillator 18 supplies an oscillation signal of 13.56 MHz as a carrier wave signal to the encoding unit 16 and the modulation unit 17 and as a clock signal to the CPU 13. The CPU 13 uses a frequency obtained by appropriately dividing the oscillation signal as an operation clock. The modulator 17 is configured to ASK-modulate a carrier wave with encoded transmission data, and is configured to be able to adjust the degree of modulation in that case. The modulated signal modulated by the modulation unit 17 is output to the antenna (LC resonance circuit coil) 19 via the amplification unit 50 and transmitted to the outside as a radio wave signal.
[0018]
On the other hand, when the antenna 19 receives a signal transmitted from the IC card 12 side, the received signal is output to the receiving unit 20. The demodulated signal demodulated by the receiving unit 20 is supplied to the decoding unit 22 via the amplification unit 21 and decoded, and then output to the CPU 13.
[0019]
Then, the CPU 13 adjusts the modulation degree in the modulation unit 17 according to the card specific data transmitted by the IC card 12 as will be described later, and also outputs the output impedance of the amplification unit 18 and the amplification factor (reception sensitivity) of the amplification unit 21. ) To adjust.
[0020]
FIG. 2 is a functional block diagram showing an electrical configuration inside the IC card 12. The IC card 12 includes an antenna (LC resonance circuit coil) 23, a rectifier 24, a clock extractor 25, a CPU 26, a memory (storage means) 27, a modulator 28, and the like.
[0021]
When the antenna 23 receives the radio wave signal transmitted from the reader / writer 11, the rectifier 24 rectifies and smoothes the received signal to supply power to the CPU 26 and the like, and supplies the demodulated data obtained by demodulating the received signal to the CPU 26. Output to. The clock extraction unit 25 supplies the CPU 26 with a clock signal extracted from the signal received by the antenna 23. The CPU 26 reads / writes data from / to a non-volatile memory 27 such as FRAM (Ferroelectric RAM).
[0022]
Further, the CPU 26 serially outputs transmission data to the modulation unit 28. The modulation unit 28 includes a series circuit of a switch 29 and a modulation load 30, and the series circuit is connected to the antenna 23 in parallel. The switch 29 is turned on / off according to the transmission data output by the CPU 26, and load-modulates the carrier wave.
[0023]
The memory 27 of the IC card 12 stores ID data of the IC card 12, a code used for authentication processing at the time of communication, data related to the user of the IC card 12 originally intended to be read by the reader / writer 11 and the like. .
[0024]
In addition, as shown in FIG. 3, data relating to manufacturing conditions unique to the IC card 12 (hereinafter referred to as card-specific data) is stored. These card-specific data are roughly classified into data relating to manufacturing management of the IC card 12 and data relating to electrical characteristics measured in the inspection process at the time of manufacturing.
[0025]
For example, the former is the manufacturer, type or model name, production line, and production time of the IC chip (CPU 26) and the IC card 12. The latter includes the current consumption value and internal resistance value of the IC chip, and the resonance frequency and Q value of the antenna 23 portion of the IC card 12. For example, the measurement is performed by the operator in the inspection process at the time of manufacturing the IC card 12. And the result is written in the memory 27. The latter data may be either an absolute value or a relative value.
These card-specific data are read from the memory 27 and transmitted to the reader / writer 11 when the IC card 12 receives a data read command transmitted by the reader / writer 11.
[0026]
Next, the operation of the present embodiment will be described with reference to FIGS. FIG. 4 is a flowchart showing a portion according to the gist of the present invention in the communication control processing performed by the CPU 13 of the reader / writer 11. When receiving a command transmission request from the host device, the CPU 13 first initializes communication conditions (step S1). That is, the modulation factor, transmission power level, reception sensitivity, etc. of the transmission signal are initialized. Then, a request command is transmitted to the IC card 12 (step S2).
[0027]
When the IC card 12 transmits the card ID in response to the request command and the reader / writer 11 receives the ID (step S3, "YES"), the CPU 13 transmits the data read command specifying the card ID. (Step S4).
[0028]
As described above, when receiving the data read command, the IC card 12 reads the card specific data from the memory 27 and transmits it to the reader / writer 11. When the CPU 13 receives the card specific data (step S5, “YES”), the CPU 13 determines communication conditions to be set based on the received card specific data (step S6), and changes to the determined conditions (step S7). .
[0029]
The determination of the communication condition in step S6 is performed based on, for example, data relating to the electrical characteristics of the IC card 12. That is, when the IC card 12 approaches the reader / writer 11, the impedance of the transmission circuit unit fluctuates due to the generation of a mutual inductance component between the antenna 23 on the IC card 12 side and the antenna 19 on the reader / writer 11 side. The modulation degree of the transmission signal changes. Accordingly, since the resonance frequency and Q value of the antenna 23 can be regarded as parameters that affect the degree of change in the modulation degree, the modulation degree and output impedance of the transmission signal are adjusted according to these values. .
[0030]
In addition, the current consumption value and the internal resistance value of the CPU 26 affect the level of the noise level generated when the CPU 26 operates. That is, the noise level increases as the fluctuation of the current consumption increases. Further, the fluctuation of current consumption varies greatly depending on whether the internal resistance value is high or low. When the IC card 12 having a relatively high noise level approaches the reader / writer 11, there is a possibility that the noise component received by the reader / writer 11 side is captured as response data, so the reception sensitivity is set lower than the standard.
[0031]
In addition, as described above, communication conditions may be set based on data related to manufacturing management of the IC card 12 as well as data related to electrical characteristics. That is, there is a case where the bias of the electrical characteristics tends to be constant depending on the manufacturer, type, and model name of the IC card 12. Therefore, even if the setting is made based on the data relating to the manufacturing management, the adjustment can be made.
[0032]
As described above, when the communication condition on the reader / writer 11 side is changed in accordance with the characteristics of the IC card 12, normal communication processing is performed thereafter. That is, the CPU 13 of the reader / writer 11 performs authentication processing with the IC card 12 (step S8), and then performs transmission / reception processing of important data (step S9). If another card is processed (step S10, “YES”), the process returns to step S1, and if another card is not processed (“NO”), the process is terminated.
[0033]
Further, the above processing has been described on the assumption that the reader / writer 11 communicates with one IC card 12 at a time. However, when a plurality of IC cards 12 communicate with one at a time, for example, two IC cards 12 are communicated. 4 may be processed according to the flowchart shown in FIG. Here, an example is shown in which the frequency is transferred between two IC cards (card a → card b). That is, (1) communication conditions are initialized in step S1, and (2) the IDs of two IC cards 12 (a, b) are received in steps S2 and S3. In that case, the card specific data a and b are read for each of the IC cards 12a and 12b in steps S4 and S5.
[0034]
Next, (3) First, the communication conditions are changed based on the card specific data a (S6, S7), and communication is performed with the IC card 12a. (4) Authentication processing (S8), (5) Important data The transmission / reception process (S9) is performed. Then, returning to step S6, (6) the communication conditions are changed based on the card specific data b (S6, S7), and communication is performed with the IC card 12b. (7) Authentication processing (S8), (8) The important data transmission / reception process (S9) is performed. (9) The communication condition is changed for the IC card 12a (S7), the "10" frequency is subtracted (S9), and the communication condition is changed for the "11" IC card 12b (S7). The frequency addition process to 12b is performed. After these series of processes, the process returns to step S1.
[0035]
As described above, according to the present embodiment, card-specific data relating to the manufacturing conditions of the IC card 12 is stored in the memory 27 of the IC card 12, and the IC card 12 has a data read request from the reader / writer 11. The data is read from the memory 27 and transmitted. When the reader / writer 11 receives the card-specific data transmitted from the IC card 12 side, the reader / writer 11 adjusts the parameters related to the communication conditions performed with the IC card 12 based on the data.
[0036]
Therefore, even if the IC card 12 is in a state of being very close to the reader / writer 11 and the electrical characteristics of the IC card 12 affect the reader / writer 11 side, the card received on the reader / writer 11 side. By adjusting the parameters relating to the communication conditions based on the unique data, it is possible to reduce the influence of the characteristics on the communication and perform the communication with each IC card 12 satisfactorily. Even if the electrical characteristics of various IC cards 12 are slightly different from each other, good communication with each IC card 12 can be performed by storing communication conditions corresponding to the characteristics. It becomes possible.
[0037]
Then, the reader / writer 11 adjusts the modulation degree of the transmission signal and the reception sensitivity of the reception signal based on the card specific data received from the IC card 12, so that the IC card 12 that is approaching is adjusted based on the received card specific data. Even when it is expected that the modulation degree of the transmission signal waveform changes due to the influence of the impedance that it has, or when it is expected that the data is erroneously received due to the influence of noise generated by the IC card 12 The degree of modulation of the transmission signal and the reception sensitivity of the reception signal can be adjusted so as to reduce the influence thereof, and communication with the IC card 12 can be performed satisfactorily.
[0038]
The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following modifications or expansions are possible.
If the IC card 12 is to transmit card-specific data to the reader / writer 11 at the stage of response to the transmission of the request command in step S3, steps S4 and S5 may be deleted.
The host device is not limited to a personal computer and may be a device dedicated to communication. Further, the function of the host device may be incorporated in the reader / writer 11.
The processing shown in FIG. 5 may be performed on three or more IC cards 12.
The communication condition may be adjusted only for one of the modulation degree of the transmission signal and the reception sensitivity.
[0039]
When the deviation of the resonance frequency value on the IC card 12 side is relatively large, the reader / writer 11 may adjust the output impedance of the amplifying unit 50 as a parameter related to communication conditions.
The data to be stored in the storage means is not limited to that shown in FIG. 3, and any data showing the manufacturing conditions of the IC card may be used.
The storage means is not limited to the FRAM but may be a one-time PROM, EPROM, EEPROM or the like.
The present invention is not limited to the reader / writer 11 and may be applied to an IC card reader having only a function of reading data stored in the IC card 12.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an electrical configuration inside a reader / writer according to an embodiment of the present invention. FIG. 2 is a functional block diagram showing an electrical configuration inside an IC card. FIG. 4 is a flowchart showing an example of stored card-specific data. FIG. 4 is a flowchart showing a portion related to the gist of the present invention in a communication control process performed by a reader / writer CPU. FIG. FIG. 6 is a diagram showing a flow of processing of the flowchart of FIG. 4 when there are two cards. FIG. 6 is a diagram showing a communication state between an IC card and a reader / writer, showing the prior art. Time chart showing the state of noise generated by operation 【Explanation of symbols】
Reference numeral 11 denotes a reader / writer (IC card reader), 12 denotes an IC card, 13 denotes a CPU (control circuit), 26 denotes a CPU (control circuit), and 27 denotes a memory (storage means).

Claims (5)

A non-contact type IC card that includes storage means for storing data relating to each unique manufacturing condition, and that reads out the data relating to the manufacturing condition and transmits it by radio signal when there is a data read request from the outside,
Upon receipt of the data relating to the manufacturing conditions transmitted by the IC card, the IC card reader is configured to adjust parameters relating to communication conditions performed with the IC card based on the data ,
When the IC card reader recognizes that there are a plurality of the IC cards in its own communication area, it reads out data related to the manufacturing conditions of each IC card, and sets parameters related to the communication conditions according to the data. A communication system for a non-contact type IC card , wherein communication is performed sequentially with the plurality of IC cards while changing . The non-contact type IC card communication system according to claim 1, wherein the parameter relating to the communication condition is a modulation degree of a transmission signal. 3. The non-contact type IC card communication system according to claim 1, wherein the parameter relating to the communication condition is a reception sensitivity of a reception signal. An IC card used in the non-contact type IC card communication system according to any one of claims 1 to 3. An IC card reader used in the non-contact type IC card communication system according to any one of claims 1 to 3.

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