JPH11219414A - Mobile information communication object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent information received by a reader-writer from being erroneously judged at the time of transmitting information to the reader-writer in non-contact state by providing a time lag between the mark of a high-order signal level and the mark of a low-order signal level arranged adjacently to each other in a slot. SOLUTION: The mark of the high-order signal level (a mark in the state of a value '1') and the mark of the low-order signal level (a mark in the state of a value '0') are included the slot and the time lag is provided between the mark of the high-order signal level and the mark of the low-order signal level arranged adjacently to each other. Therefore, even in the case when distortion is caused in the waveform of the mark of the high-order signal level in the slot transmitted from a mobile information communication object, the influence of the distortion to the position of the mark of the adjacent low-order level is reduced. Thereby, it is ensured to obtain correct information based on a received signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of allocating a state of a slot including a mark of an upper signal level and a mark of a lower signal level in a predetermined combination to a bit having a value of "1". A mobile information communication body such as an IC card that transmits information to a reader / writer in a non-contact manner by allocating a slot state in which a level mark and a lower signal level mark are included in another combination to bits of “0” value. In particular, the present invention relates to a mobile information communication body that prevents information received by a reader / writer from being erroneously determined.

[0002]

2. Description of the Related Art For example, an IC card formed by embedding a microcomputer chip and a memory chip on a card substrate having a size similar to that of a credit card or the like has been put to practical use in various fields such as finance, distribution, transportation, and medicine. Is planned. In an IC card system using such an IC card, for example, power is transmitted from a reader / writer to the IC card, and information such as control codes and data is communicated between the reader / writer and the IC card.
In power transmission and information communication between a reader / writer and an IC card, in addition to a contact method in which terminals are brought into contact with each other, a non-contact method in which electromagnetic waves are used is employed.

FIG. 5 shows an example of an IC card system employing a non-contact method. This system includes a non-contact IC card 1 having an antenna, a reader / writer 2 having an antenna T, An information processing device (not shown) is provided. The reader / writer 2 is a personal computer (personal computer) via, for example, an interface or a LAN.
And the like. In the information processing apparatus, for example, processing of information received from the reader / writer 2 via an interface or the like, such as data on finance, distribution, traffic, medical care, and the like, is performed.

For example, in information transmission from the IC card 1 to the reader / writer 2, information to be transmitted is encoded and modulated into bit information, and a signal corresponding to a bit of “1” value or a signal of “0” value is encoded. The signal corresponding to the bit may be transmitted from the IC card 1. In this case, the reader / writer 2 may, for example, store a plurality of IC cards 1 in the communicable area.
, The signal of the bit of “1” value and the signal of the bit of “0” are simultaneously transmitted from these IC cards 1 and the situation where the IC card 1 does not exist in the communicable area is also received. It is necessary to make a determination based on the obtained signal.

[0005] Therefore, in information communication from the IC card 1 to the reader / writer 2, generally, a bit of “1” value or “0” is provided for each slot including a combination of an upper signal level mark and a lower signal level mark. The process is performed by assigning a bit of "value". Here, the upper signal level mark is, for example, a mark in which the signal level is equal to or higher than a predetermined threshold, and the lower signal level mark is a mark in which the signal level is lower than the predetermined threshold. It is.

Specifically, for example, while assigning the state of the slot shown in FIG.
The state of the slot shown in (b) is assigned to a bit having a value of “0”, and information is transmitted from the IC card 1 to the reader / writer 2. Here, in the slot shown in FIG. 6A, a mark of an upper signal level (a mark of a state of “1” value) and a mark of a lower signal level (a mark of a state of “0” value) are continuous. 6B, the upper signal level mark and the lower signal level mark in the slot shown in FIG. 6A are included in the slot shown in FIG. 6B. Are included in a mutually inverted manner.

[0007] Information communication between the IC card 1 and the reader / writer 2 is performed by establishing synchronization using, for example, a clock signal. In the IC card 1, a slot allocated for information transmission to the reader / writer 2 is allocated. FIG. 6 (a)
Alternatively, by transmitting the signal having the waveform shown in FIG. 6B, the bit of “1” value or the bit of “0” value is transmitted to the reader / writer 2. On the reader / writer 2 side,
The signal received from the IC card 1 is processed as "1" bit or "0" bit for each slot.

If it is assumed that the waveform of the signal transmitted from the IC card 1 is received by the reader / writer 2 without change, the waveform (ideal waveform) of the signal received by the reader / writer 2 is, for example, an IC card that can communicate. When the IC card 1 does not exist, the state is as shown in FIG. 6C. Also, when only one communicable IC card exists and the IC card 1
FIG. 6 shows a case where a signal in a slot state having a value of 1 ″ is transmitted.
As shown in FIG. 6D, when only one communicable IC card 1 exists and a signal in the slot state of “0” value is transmitted from the IC card 1, FIG. In addition, there are a plurality of communicable IC cards 1, and a signal of a slot state of “1” value and a signal of a slot state of “0” value are simultaneously transmitted from these IC cards 1. In this case, the result is as shown in FIG.

The signal waveform shown in FIG. 6 (c) is a no-signal state, and in the signal waveform shown in FIG. 6 (f), only the upper signal level mark is included in the slot. The signal waveforms shown in FIGS. 6D and 6E are the same as the waveforms shown in FIGS. 6A and 6B, respectively. In the reader / writer 2, based on the states of the four types of reception waveforms described above, FIG.
The four types of communication states shown in FIGS. 6D, 6E, and 6F are determined.

FIGS. 7 (a) and 7 (b) show other examples of the slot states assigned to the "1" value bit and the "0" value bit, respectively.
In the slot shown in (a), a mark of an upper signal level, a mark of a lower signal level, and a mark of an upper signal level are included in the stated order from the left side of FIG.
In the slot shown in FIG. 7B, the upper signal level mark and the lower signal level mark in the slot shown in FIG.

As described above, FIG. 7A and FIG.
The signal waveform shown in (b) is a bit of “1” value and “0”.
When used as value bits,
The received waveforms (ideal waveforms) at the reader / writer 2 corresponding to the respective communication situations shown in (c), (d), (e), and (f) of FIG. , FIG.
(D), as shown in FIGS. 7 (e) and 7 (f).

Here, an ideal case has been described in which the waveform of a signal transmitted from the IC card 1 is received by the reader / writer 2 without change, but in an actual system, for example, the IC card 1 Since the signal transmitted from the transmission line generates noise on the transmission line and the like,
The reader / writer 2 removes noise of the signal received from the IC card 1 using a filter, and the like. For this reason, the waveform of the signal received and processed by the reader / writer 2 is distorted, such as being distorted, as compared with the waveform of the original signal transmitted from the IC card 1. FIG. 8 shows an example of such a waveform distortion. For example, a square wave signal as shown in FIG.
Even when transmitted from the card 1, the waveform of the signal received and processed by the reader / writer 2 is distorted as shown in FIG.

FIG. 9 shows an example of the waveform of a signal that is received and processed by the reader / writer 2 from the IC card 1 in a real system, for example, when the communicable area of the reader / writer is relatively small. Note that in FIG.
6A shows a case where the signal waveforms in the slot state shown in FIG. 6B are used as “1” value bits and “0” value bits, respectively.

FIG. 9A shows a signal waveform in the slot state of "1" value transmitted from the IC card 1, for example, and FIG. 9B shows that the reader / writer 2
When the reception level of the signal received from the card 1 is the maximum, that is, when the two are close to each other, a distorted signal waveform when the reader / writer 1 receives and processes the signal is shown. is there.

Here, generally, when the distance between the reader / writer 2 and the IC card 1 increases, the reader / writer 2
Since the reception level of the signal received from the C card 1 is reduced, the signal received from the IC card 1 is amplified by, for example, a constant gain in the reader / writer 2, and FIG. The waveform of the signal thus amplified is shown. When the communicable area of the reader / writer 2 is relatively small, the reception level of a signal received from the IC card 1 with which the reader / writer 2 can communicate is equal to the I level.
Irrespective of the position where the C card 1 exists, there is not much change.

The reader / writer 2 compares the signal level of the distorted signal waveform shown in FIG. 9B with, for example, a predetermined judgment level, and determines whether the signal level of the signal waveform is higher than the judgment level. Is used as a mark of the upper signal level, and a portion where the signal level of the signal waveform is lower than the determination level is used as a mark of the lower signal level, whereby the distorted signal waveform shown in FIG. Demodulate the square signal waveform shown in c). In this way, the reader / writer 2 obtains bit information of “1” value based on the signal received from the IC card 1.

FIG. 9D shows a signal waveform in the slot state of "1" value transmitted from, for example, the IC card 1, and FIG. 9E shows the reader / writer 2
Is distorted when the reader / writer 1 receives and processes the signal when the reception level of the signal received from the IC card 1 is the minimum, that is, when the two are farthest from each other to the extent that they can communicate. The signal waveform is shown. in this case,
In the reader / writer 2, in the same manner as described with reference to FIG. 9B and FIG. 9C, the square signal waveform shown in FIG. Demodulate. In this way, the reader / writer 2 obtains bit information of “1” value based on the signal received from the IC card 1.

[0018]

However, in the information communication from the IC card 1 to the reader / writer 2 using the above-mentioned slot state, for example, the waveform of the mark of the upper signal level included in the slot is used. In this case, the influence of the distortion of the signal reaches the position of the adjacent lower signal level mark, and the reader / writer 2 mistakenly recognizes that the portion in the slot which is actually the lower signal level mark is the upper signal level mark. There is a problem that the operation may be performed.

A specific example of such a problem will be described with reference to FIG. FIG. 1 shows an example of a waveform of a signal received and processed by the reader / writer 2 from the IC card 1 when, for example, the communicable area of the reader / writer is relatively large. 6A and 6B show the case where the signal waveforms in the slot state shown in FIGS. 6A and 6B are used as “1” value bits and “0” value bits, respectively.

FIG. 10A shows a signal waveform in the slot state of "1" value transmitted from the IC card 1, for example, and FIG. 10B shows that the reader / writer 2 When the reception level of the signal received from the card 1 is the maximum, that is, when the two are close to each other, a distorted signal waveform when the reader / writer 1 receives and processes the signal is shown. is there.

Here, in general, when a relatively communicable area of the reader / writer 2 is ensured, compared with a case where the area is relatively narrow, the IC card which is the most communicable with the reader / writer 2 can be used. Since the reception level of the signal received from 1 is low, the reader / writer 2 amplifies the received signal with a larger gain than when the communicable area is relatively narrow, for example. FIG. 10B shows a waveform of a signal amplified with a relatively large gain in this way, for example.

The reader / writer 2 compares the signal level of the distorted signal waveform shown in FIG. 10B with, for example, a predetermined judgment level in the same manner as described with reference to FIG. Thus, while the signal level of the signal waveform is equal to or higher than the determination level as a mark of the upper signal level,
By setting a portion where the signal level of the signal waveform is lower than the determination level as a mark of the lower signal level, the above-described FIG.
A square signal waveform shown in FIG. 10C is demodulated from the distorted signal waveform shown in FIG.

However, as shown in FIG. 10 (c), for example, when the waveform of the mark of the upper signal level contained in the slot becomes large, the demodulated upper signal level of the upper signal level becomes larger. In such a case, the width of the mark is increased to, for example, about twice as large as the original width. In such a case, the mark of the higher signal level whose width has been expanded after demodulation is the mark of the lower signal level adjacent to the mark. May be affected. In the reader / writer 2, for example, the IC card 1
The state of the demodulated waveform at the points "C" and "D" shown in FIG. 10C is determined (strobe) based on the synchronization secured between the steps (a) and (b). In such a case, a portion (point "D" in the figure) that is actually a mark of a lower signal level is erroneously determined to be a mark of an upper signal level.

That is, in such a case, although only one IC card 1 actually exists in the communicable area of the reader / writer 2, the reader / writer 2 There is a problem that it is recognized that a plurality of IC cards 1 exist.

FIG. 10 (d) shows a signal waveform in the slot state of "1" value transmitted from the IC card 1, for example, and FIG. 10 (e) shows the reader / writer 2 Is distorted when the reader / writer 1 receives and processes the signal when the reception level of the signal received from the IC card 1 is the minimum, that is, when the two are farthest from each other to the extent that they can communicate. The signal waveform is shown, and
FIG. 10F shows a square signal waveform demodulated from the distorted signal waveform by using the determination level.

As a method for avoiding the above-mentioned problems, for example, the gain value when the received signal is amplified by the reader / writer 2 using the control such as automatic gain control (AGC) is changed according to the reception level. It is possible to reduce the influence of signal waveform distortion to some extent, but if such a method is used, for example, the reader / writer must be equipped with a circuit that performs automatic gain control, so that the receiving circuit There are problems such as the complexity of the automatic gain control and the cost of the circuit for performing the automatic gain control. Avoidance was strongly required.

The present invention has been made to solve such a conventional problem, and the state of a slot including a mark of an upper signal level and a mark of a lower signal level in a predetermined combination is set to a "1" value. , While the state of the slot in which the upper signal level mark and the lower signal level mark in the slot are included in another combination
A mobile information communication device, such as an IC card, which can prevent information received by the reader / writer from being erroneously determined when information is transmitted to the reader / writer in a non-contact manner by allocating to a bit having a value of 0 ”. The purpose is to provide.

[0028]

In order to achieve the above object, in a mobile information communication system according to the present invention, a state of a slot including a mark of an upper signal level and a mark of a lower signal level in a predetermined combination is described. On the other hand, while assigning to a bit having a value of "1", the state of a slot including a mark of an upper signal level and a mark of a lower signal level in the slot in another combination is assigned to a bit of a value of "0", and the slot is assigned to a reader / writer. When information is transmitted by contact, a time lag is provided between the adjacent upper and lower signal level marks in the slot.

Therefore, even if the waveform of the mark of the upper signal level in the slot transmitted from the mobile information communication body is distorted, as described above, the mark of the upper signal level and the adjacent mark of the upper signal level are compared. Since there is a time lag between the mark of the signal level and the mark of the upper signal level, it is possible to reduce the influence of the distortion of the mark of the upper signal level on the position of the mark of the adjacent lower signal level. By setting a time lag with a time width that does not affect the determination of the lower signal level mark, the reader / writer is prevented from erroneously determining the upper signal level mark and the lower signal level mark. can do. Thereby, for example, even when the communicable area of the reader / writer is relatively large,
It is possible to guarantee that the reader / writer obtains accurate information based on the signal received from the mobile information communication body.

Here, any combination may be used as the predetermined combination of the upper signal level mark and the lower signal level mark in the above-described slot. It is possible to prevent the writer from misidentifying the mark of the upper signal level and the mark of the lower signal level. Also, for example, the number of marks included in the slot may be arbitrary. In addition, as a mode of transmitting information from the mobile information communication body to the reader / writer, any mode may be used as long as the information is transmitted in a non-contact manner.

The mobile information communication body referred to in the present invention includes:
Not only the IC card described above, but also, for example, a name plate attached to a person, a tag attached to a product or article, an identification plate attached to livestock, or a delivery destination plate attached to parcels of parcel delivery service And a delivery destination plate attached to the container. The mobile information communication body to which the present invention can be applied is not limited to the above-described mobile information communication body, and the present invention is not limited to the above-described slot state and the bit of “1” value and “0” value. The present invention can be widely applied to various mobile information communication bodies that transmit information to a reader / writer in a non-contact manner by using the assignment.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to the drawings. In this example, the mobile information communication body is an IC
5 shows a case where the present invention is applied to a card, and an IC card 1 having an antenna, similarly to the system shown in FIG.
, A reader / writer 2 having an antenna T, and an information processing device connected to the reader / writer 2.
The C card system will be described as an example. In this example, the same reference numerals as those shown in FIG. 5 will be used for the symbols of the IC card 1, the reader / writer 2, and the antenna T of the reader / writer 2.

The IC card 1 is, for example, an antenna for communicating information in a non-contact manner, a memory for reading and writing data such as finance, distribution, traffic, medical care, etc., and control by operating these means. It is composed of a control transmission / reception unit and the like. The control transmission / reception unit includes, for example, a microcomputer having a memory storing a control program and a CPU executing the program, and a transmission / reception circuit, and stores information such as data read from the memory in a form suitable for wireless communication. It has a function of performing a process of converting the information into data and transmitting the data from the antenna, a process of demodulating information such as data received by the antenna, and writing the information in a memory, and the like.

For the operating power of the IC card 1, for example, a configuration in which a power supply is provided inside the IC card 1 may be used. For example, the IC card 1 may supply power from the reader / writer 2 in a non-contact manner. A configuration for receiving power may be used. In the configuration in which the IC card 1 receives power in a non-contact manner as in the latter case, the IC card 1 includes, for example, an antenna that receives power in a non-contact manner, and an IC that uses power received by the antenna as operating power. Features are provided. Further, in the IC card 1 that receives power in a non-contact manner as described above, for example, the power supply may not be provided inside.

With such a configuration, in the IC card 1 of the present embodiment, in the communicable area of the reader / writer 2, a state of a slot corresponding to a bit of "1" value or a bit of "0" value described later is used. The information is transmitted to the reader / writer 2 in a non-contact manner, and the information is received from the reader / writer 2 in a non-contact manner. When power is transmitted from the reader / writer 2 to the IC card 1 in a non-contact manner, the IC card 1 receives power from the reader / writer 2 in a non-contact manner together with the information communication described above.

The reader / writer 2 includes an antenna T for communicating information in a non-contact manner, an interface for communicating information with an information processing apparatus, and a control transmitting and receiving unit for controlling these units by functioning them. It is configured. The control transmission / reception unit includes, for example, a microcomputer having a memory storing a control program and a CPU executing the program, and a transmission / reception circuit, and transmits information such as data received from an information processing apparatus via an interface. It has a function of performing a process of converting the data into a form suitable for wireless communication and transmitting the data from the antenna T, a process of demodulating information such as data received by the antenna T, and transmitting the demodulated information to the information processing device via the interface. I have.

Further, for example, since a signal transmitted from the IC card 1 generates noise on a transmission line or the like, the reader / writer 2 of this embodiment is provided with a function for removing signal noise such as a filter. The reader / writer 2 removes noise of a signal received from the IC card 1 using a filter or the like. In this example, it is assumed that the communicable area of the reader / writer 2 is relatively large, and that the reader / writer 2 has a function of amplifying a signal received from the IC card 1 with a fixed gain, for example. With this function, the reader / writer 2 ensures that even a signal having a small reception level, for example, received from a communicable IC card 1 which is present at a relatively remote location, is amplified to a relatively large signal level and processed. I have.

With such a configuration, the reader / writer 2 of the present example communicates information with the IC card 1 existing in the communicable area. In this example, it is assumed that the waveform of the signal received from the IC card 2 is distorted due to, for example, the reader / writer 2 processing the signal received from the IC card 1 with a filter as described above. I do.

When power is transmitted from the reader / writer 2 to the IC card 1 in a non-contact manner, the reader / writer 2 includes, for example, an antenna for transmitting power in a non-contact manner,
A function is provided for transmitting power received from an external power supply (not shown) from the antenna. In the information processing device,
For example, processing of information such as financial, distribution, traffic, medical data and the like received from the reader / writer 2 via an interface or the like is performed.

Information communication between the IC card 1 and the reader / writer 2 is performed by establishing synchronization using, for example, a clock signal, and the IC card 1 is assigned to information transmission to the reader / writer 2. The signal state in the slot is controlled, and bit information of “1” value or bit information of “0” value is transmitted to the reader / writer 2 for each slot. As described above, in the IC card 1 of the present embodiment, the information to be transmitted is encoded and modulated into the information composed of the information of the bit of “1” value and the information of the bit of “0” value, and the reader / writer performs 2 for transmitting information. Also,
The reader / writer 2 processes the signal received from the IC card 1 as "1" bit information or "0" bit information for each slot.

Here, from the IC card 1 to the reader / writer 2
The information communication to is described in detail. FIG. 1 shows the state of slots used for transmitting information from the IC card 1 to the reader / writer 2 in this example. In this example,
The state of the slot shown in FIG. 1A is assigned to a bit of “1” value, while the state of the slot shown in FIG. 1B is assigned to a bit of “0” value.

In the slot shown in FIG. 1A, a mark of an upper signal level (a mark of "1" value in this example) and a mark of a lower signal level (in this example, a state of "0" value) ), And a time lag is provided between the mark of the upper signal level and the mark of the lower signal level arranged adjacent to each other in this manner. In the slot shown in FIG. 1B, the mark of the upper signal level and the mark of the lower signal level in the slot shown in FIG. In FIG. 1A and FIG. 1B, the time width of the mark of the upper signal level and the mark of the lower signal level are set to "
a) and the time width of the time lag is “L”.
It is shown as Further, in this example, the case where the time width “L” of the time lag is about half of the time width “a” of the mark is shown.

The reception of information from the IC card 1 performed by the reader / writer 2 of this embodiment will be described with reference to FIG. FIG. 3 shows a case where the reception level of a signal received by the reader / writer 2 from the IC card 1 is relatively high, that is, a case where the two are relatively close to each other compared to the size of the communicable area. Is shown. FIG. 2A shows a signal waveform in the slot state of “1” value transmitted from, for example, the IC card 1, and FIG.
3 shows a distorted signal waveform when the reader / writer 2 receives and processes the signal.

Here, in the reader / writer 2, FIG.
By comparing the signal level of the distorted signal waveform shown in (b) with, for example, a predetermined determination level, a portion where the signal level of the signal waveform is equal to or higher than the determination level is marked as a higher signal level, while By setting a portion where the signal level of the signal waveform is lower than the determination level as a lower signal level mark, a square signal waveform is demodulated from the distorted signal waveform shown in FIG. It is determined whether the state of the slot related to the received signal is bit information of “1” value or bit information of “0” value.

In this case, in this example, since a time lag is provided between the upper signal level mark and the lower signal level mark in the slot as shown in FIG. The influence of the distortion generated on the signal of the second mark on the position of the mark of the adjacent lower signal level is reduced. For this reason, in the reader / writer 2,
For example, when judging the state of the waveform demodulated at the points "A" and "B" shown in FIG. 2B based on the synchronization secured with the IC card 1, at the point "A" The state of the mark of the upper signal level is accurately determined, and at the point "B", the state of the mark of the lower signal level is accurately determined.

FIG. 2C shows a signal waveform in the slot state of "0" value transmitted from, for example, the IC card 1, and FIG. 2D shows that the reader / writer 2 A distorted signal waveform when a signal is received and processed is shown. Here, the reader / writer 2 compares the signal level of the distorted signal waveform shown in FIG. 2D with the set determination level, as in the case shown in FIG. A rectangular signal waveform is demodulated from the signal waveform, and based on the demodulated signal waveform, whether the state of the slot related to the received signal is bit information of “1” value or “0”
It is determined whether the information is bit information of the value.

In this case, as in the case shown in FIG. 2B, a time lag is provided between the upper signal level mark and the lower signal level mark in the slot. Even if the waveform of the mark of the signal level is distorted, the reader / writer 2 accurately determines that the mark of the lower signal level is at the point "A" shown in FIG. 2D, for example. At the same time, at the point "B" shown in the figure, it is accurately determined that the state is the mark of the higher signal level.

In FIG. 2E, for example, there are a plurality of IC cards 1 in the communicable area of the reader / writer 2 and the slot state of the “1” value simultaneously transmitted from these IC cards 1 is shown. The figure shows a distorted signal waveform when the reader / writer 2 receives a signal and a signal in a slot state of a “0” value when the reader / writer 2 receives and processes these signals.

Here, in the reader / writer 2, FIG.
As in the case shown in FIG. 2B, the signal level of the distorted signal waveform shown in FIG. 2E is compared with the set determination level, and a square signal waveform is demodulated from the signal waveform. Then, it is determined based on the demodulated signal waveform whether the state of the slot related to the received signal is bit information of "1" value or bit information of "0" value. In this case, the reader / writer 2 determines, for example, that the mark is at the higher signal level at both the “A” point and the “B” point shown in FIG. Thereby, it is grasped that a plurality of IC cards 1 exist in the communicable area.

FIG. 2F shows a case where the IC card 1 does not exist in the communicable area of the reader / writer 2, for example.
The signal waveform received by the reader / writer 2 is shown. In this case, no signal is received by the reader / writer 2 because there is no IC card 1 that can communicate with the reader / writer 2. For this reason, in the process of determining whether the slot state related to the received signal is bit information of “1” value or bit information of “0” value in the reader / writer 2, for example, 2 (f) "
At both points A "and" B ", it is determined that the state of the mark is at the lower signal level, whereby it is determined that the IC card 1 does not exist in the communicable area.

It should be noted that the table shown in FIG. 3 shows the above-mentioned four tables of FIGS. 2 (b), 2 (d), 2 (e) and 2 (f).
The determination results of signal waveforms at points "A" and "B" in various types of communication situations are shown together. As shown in the drawing, in the reader / writer 2, one communicable IC card is used.
When there is only one IC card 1 and a signal in the slot state of “1” value is transmitted from the IC card 1, there is only one communicable IC card 1 and the slot of “0” value is transmitted from the IC card 1. When the state signal is transmitted, a plurality of communicable IC cards 1 exist, and a signal of the slot state of “1” value and a signal of the slot state of “0” value are simultaneously transmitted from these IC cards 1. When it is transmitted,
It is possible to reliably determine four types of communication situations, such as when the C card 1 does not exist.

As described above, the IC performed in this embodiment
In the information communication from the card 1 to the reader / writer 2, even if the waveform of the mark of the upper signal level in the slot transmitted from the IC card 1 is distorted, for example, the distortion is not reflected on the adjacent lower signal. It is possible to reduce the influence on the position of the mark of the level. For example, by setting a time lag in such a time width that the influence of the distortion does not affect the determination of the mark of the lower signal level, the reader / writer can be set. Can be prevented from erroneously determining the mark of the upper signal level and the mark of the lower signal level. Thus, for example, even when the communicable area of the reader / writer is relatively large, it is possible to guarantee that the reader / writer 2 obtains accurate information based on the signal received from the IC card 1.

Further, in the IC card 1 of this embodiment, as described above, the information to be transmitted is represented by a bit having a value of “1” and a bit having a value of “0”.
When encoding and modulating information composed of value bits and transmitting it, a time lag is provided between a mark of an upper signal level and a mark of a lower signal level in a slot so that encoding and modulation are performed. Therefore, for example, while the area (detectable area) in which the reader / writer 2 can detect the IC card 1 is expanded, the reader / writer 2
Optimal information encoding can be realized in accordance with the use state of the system and the like so that it is possible to guarantee that information received from the C card 1 is accurately demodulated.

Further, in the configuration in which the influence of the distortion generated in the signal waveform is avoided by using the IC card 1 of this embodiment, for example, it is not necessary to provide the reader / writer 2 with a function of performing automatic gain control. Compared with the case where the reader / writer 2 is provided with a function to perform the above and the effect of reducing the influence of the signal waveform distortion is used, the configuration of the receiving circuit of the reader / writer is not complicated, and the cost is reduced. There is an advantage that there is no squat.

The time width of the time lag provided between the adjacent upper signal level mark and lower signal level mark in the slot shown in FIG. The time width may be set arbitrarily in accordance with, for example, a time width that can reduce the influence of distortion generated in the waveform of the mark of the upper signal level on the position of the mark of the adjacent lower signal level to a practically effective degree. It is preferable to set the time lag. The setting of the time width of the time lag is performed by, for example, a data transfer speed between the IC card 1 and the reader / writer 2, a synchronization interval in information communication, and noise generated in a transmission path or transmission / reception processing, for example. This is performed based on the magnitude of the influence of, for example, the characteristics of the filter processing performed by the reader / writer 2, and the like.

The interval between the "A" point and the "B" point shown in FIG. 2, which is a reference point for determining the slot state in the reader / writer 2, is determined, for example, at the "A" point. To reduce the influence of the distortion generated in the mark of the upper signal level to be performed on the position of the point "B",
It is preferable to set an interval that is at least as long as the certainty at the point "B" can be guaranteed. In addition,
If the interval is too large, the position of the point "B" deviates from the position of the mark to be originally determined and the position of the "B"
Since an error occurs in the determination at the point, the state in the slot to be originally determined at the points "A" and "B" can be reliably determined in consideration of the balance of the above matters. Preferably, a distance between the two points is used.

FIG. 4 shows another example of the state of the slot used for transmitting information from the IC card 1 to the reader / writer 2. In the example of FIG. 4, the state of the slot shown in FIG. 4A is assigned to a bit of “1” value, while the state of the slot shown in FIG. 4B is assigned to a bit of “0” value. ing.

In the slot shown in FIG. 4A, the upper signal level mark (mark of "1" value state), the lower signal level mark (mark of "0" value state), the upper signal level mark The level marks are included in the order of description from the left side of the figure, and a time lag is provided between the adjacently arranged upper signal level marks and lower signal level marks. In the slot shown in FIG. 4B, the upper signal level mark and the lower signal level mark in the slot shown in FIG.

In FIG. 4A and FIG. 4B, the time width of the upper signal level mark and the lower signal level mark is indicated by "b", and the time width of the mark is located on the left side in the slot in the figure. The time width of the time lag is shown as “M”, while the time width of the time lag located on the right side in the slot is shown as “N” in the figure. Here, the time widths “M” and “N” of these two time lags may be the same or different.

In the case of performing information communication from the IC card 1 to the reader / writer 2 using the state of the slot shown in FIG. 4, even when the upper signal level mark and the lower signal level mark in the slot are used. Since a time lag is provided therebetween, for example, it is possible to reduce the influence that distortion generated in the waveform of the mark of the upper signal level in the slot transmitted from the IC card 1 affects the position of the mark of the adjacent lower signal level. This makes it possible to guarantee that the reader / writer 2 obtains accurate information based on the signal received from the IC card 1 even if the communicable area of the reader / writer is relatively large, for example. .

Here, the state of the slot used in the information communication from the IC card to the reader / writer is not necessarily limited to the state shown in the above embodiment. For example, the upper signal level mark and the lower signal included in the slot are included. The combination with the mark of the level and the number of marks are not necessarily limited to those shown in FIGS. 1 and 4, and various modes of the slot state may be used.

The magnitudes of the upper signal level and the lower signal level used in the information communication from the IC card to the reader / writer are not necessarily limited to those described in the above embodiment, and the magnitudes of the levels are as follows. For example, a configuration in which the upper signal level is set to a positive signal level and the lower signal level is set to a negative signal level may be used. In the present invention, the upper signal level of the adjacent upper signal level may be used. By providing a time lag between the mark and the mark of the lower signal level, for example, reducing the influence of distortion generated in the waveform of the mark of one signal level affecting the position of the mark of the adjacent other signal level Can be.

In the IC card shown in the above embodiment, the CPU executes a control program in a hardware resource including a processor such as a CPU and a memory, thereby transmitting information to a reader / writer. However, in the mobile information communication body according to the present invention, each functional means for executing such processing may be configured as an independent hardware circuit.

In the above-described embodiment, the reader / writer is connected to the external information processing device, and the information communicated with the IC card by the reader / writer is processed by the information processing device. For example, a configuration in which an information communication function provided in a reader / writer and an information processing function provided in an information processing device are integrated may be used. In this configuration, the reader / writer side is configured as a device having both a function of performing information communication processing with the IC card and a function of processing received information and the like. It does not have to be connected.

In the above-described embodiment, the case where the present invention is applied to an IC card as a mobile information communication body has been described. However, in the present invention, the reader / writer is transmitted to the reader / writer using the slot state as shown in the above-described embodiment. The present invention may be applied to any mobile information communication body that transmits information in a non-contact manner.
Also, as the configuration of the mobile information communication body, any configuration may be used as long as it transmits information to the reader / writer in a non-contact manner using the slot state as described in the above embodiment. For example, any antenna may be used as an antenna for transmitting information to a reader / writer without contact. Also, for example, when a mobile information communication body performs non-contact information communication with a reader / writer and performs non-contact power transmission, an antenna for communicating information and an antenna for receiving power are provided as separate antennas. The antennas may be configured, or these antennas may be shared by one antenna.

[0066]

As described above, according to the mobile information communication system of the present invention, the state of a slot containing a mark of an upper signal level and a mark of a lower signal level in a predetermined combination is a value of "1". While the bits are assigned to bits, the state of the slot in which the upper signal level mark and the lower signal level mark in the slot are included in another combination is "0".
Allocated to the bits of the value, when transmitting information to the reader / writer in a non-contact manner, because a time lag is provided between the upper signal level mark and the lower signal level mark arranged adjacently in the slot, for example, Even if the waveform of the mark of the upper signal level in the slot transmitted from the mobile information communication body is distorted, the influence of the distortion on the position of the mark of the adjacent lower signal level is reduced. This makes it possible to ensure that the reader / writer obtains accurate information based on the signal received from the mobile information communication body even when the communicable area of the reader / writer is relatively large, for example. it can.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a state of a slot according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining determination of a received waveform performed by a reader / writer.

FIG. 3 is a table showing a correspondence between a reception state in a reader / writer and a determination of a reception waveform.

FIG. 4 is a diagram for explaining another example of the state of the slot according to the present invention.

FIG. 5 is an example of an IC card system.

FIG. 6 is a diagram for explaining a conventional slot state.

FIG. 7 is a diagram for explaining another example of a conventional slot state.

FIG. 8 is a diagram for explaining distortion occurring in a signal waveform.

FIG. 9 is a diagram for explaining determination of a received waveform in a reader / writer according to a conventional example.

FIG. 10 is a diagram for explaining determination of a received waveform in a reader / writer according to a conventional example.

[Explanation of symbols]

1. IC card, 2. Reader / writer, T. Antenna,

Claims (1)

[Claims] 1. A state of a slot including a mark of an upper signal level and a mark of a lower signal level in a predetermined combination is assigned to a bit of "1" value, and a mark of an upper signal level and a lower signal in the slot are assigned. In a mobile information communication body that assigns a state of a slot that includes a level mark and another combination to a bit of “0” value and transmits information to a reader / writer in a contactless manner, the mobile information communication body is arranged adjacent to the slot. A time lag provided between the upper signal level mark and the lower signal level mark.