CN107273964A - Wireless tag device, wireless tag communication device, and wireless tag communication system - Google Patents

Abstract

The invention discloses a wireless tag device, a wireless tag communication device and a wireless tag communication system. The wireless tag device is strong against obstacles, and suppresses data conflicts output from the wireless tag device. The wireless tag device includes a plurality of wireless tags and first part. The first part causes at least one first wireless tag among the plurality of wireless tags to have a different directionality from other wireless tags.

Description

Wireless tag device, wireless tag communication device, and wireless tag communication system

This application claims the priority of two Japanese applications with an application date of November 02, 2016, application number JP2016-214944, and an application date of April 06, 2016, application number JP2016-076826, and cites the above applications The content and priority content are deemed to be all described in this application.

technical field

Embodiments of the present invention relate to a wireless tag device, a wireless tag communication device, and a wireless tag communication system that change and adjust the output range of radio waves output by a wireless tag.

Background technique

In recent years, wireless tags that store identification information have become popular, and they are not only attached to products, equipment, etc., but also attached to buildings, roads, etc., and have begun to be managed. As a wireless tag, there is an RFID tag (RFID: Radio Frequency IDentifier: Radio Frequency Identification) that stores identification information and the like and performs short-range wireless communication of several cm to several m. When the RFID tag is read by the wireless tag communication device (reader), product information, location information, etc. can be obtained through the information associated with the read identification information.

When the wireless tag is damaged or the like, the wireless tag cannot be read by the wireless tag communication device. In order to avoid this unreadable situation, it is conceivable to integrate a plurality of wireless tags into one unit, install the unit unit, and attach it to an article or the like. At this time, assuming that one wireless tag is obstructed, the wireless tag communication device can also obtain information in units of cells by reading other wireless tags.

In addition, there is also disclosed a system that can read identification information even when a tag fails by using a plurality of wireless tags with different frequencies and protocols for reading.

Here, referring to FIG. 12 , an example in which a wireless tag communication device reads a wireless tag while moving will be described. The wireless tag communication device moves in the direction indicated by the arrow in FIG. 12 , and passes over a wireless tag unit having a plurality of wireless tags. In this example, the wireless tag communication device passes over the wireless tag unit at t2. The wireless tags entering the radio wave range of the wireless tag communication device output identification information (hereinafter referred to as tag ID as necessary), and the wireless tag communication device reads these tag IDs.

As in this example, when there is a relative speed between the wireless tag communication device and the wireless tag, since it becomes a simple reading process, when the wireless tag of the same protocol is used, when the wireless tag communication device passes The two wireless tags are activated approximately at the same time. If activated simultaneously, these tags may respond at the same time, and the response signals (electric waves) may overlap (collide) in space, and the tag ID may not be accurately read on the wireless tag communication device side. In this case, the wireless tag communication device on the receiving side treats it as invalid data and handles it as an error.

On the other hand, in order to avoid the above-mentioned conflict, if wireless tags with different frequencies and protocols are used, the operation and reading method in the wireless tag communication device will become complicated. Therefore, the corresponding reading operation takes time (requires time), and the wireless tag communication device may move and be out of the radio wave range before the reading is completed.

Contents of the invention

In view of the above problems, the technical problem to be solved by the present invention is to provide a wireless tag device, a wireless tag communication device and a wireless tag communication system, the wireless tag device is strong against obstacles, and the collision of data output from the wireless tag device is suppressed.

To solve the above problems, an embodiment of the present invention provides a wireless tag device, including: a plurality of tags and a first component. The first part causes at least one first wireless tag among the plurality of wireless tags to have a different directionality from other wireless tags.

According to such a configuration, the wireless tag device is strong against obstacles, and it is possible to suppress collision of data output from the wireless tag device.

For a wireless tag device, in a possible implementation manner, the first component restricts a radiation direction of radio waves output from the wireless tag.

According to such a configuration, collision of radio waves output from the wireless tags can be avoided.

For a wireless tag device, in a possible implementation manner, the first component is a wall component that blocks radiation from the wireless tag.

According to such a configuration, the radio wave output from the wireless tag has directivity deviated from a direction in which no wall member is provided.

For the wireless tag device, in a possible implementation manner, the first component is an inclined component having an inclined surface forming a height difference, and the wireless tag is arranged on the inclined surface of the inclined component.

According to such a configuration, by providing the inclined member, it is possible to make the orientation of each wireless tag different.

For a wireless tag device, in a possible implementation manner, the first component is performed by any device or both devices in the wireless tag device and the wireless tag communication device that communicates with the wireless tag device. In the direction of the relative motion formed by the movement, the first wireless tag has a different orientation than other wireless tags.

According to such a configuration, the first wireless tag can be read first without data collision.

For the wireless tag device, in a possible implementation manner, each wireless tag of the plurality of wireless tags at least stores different identification information corresponding to each wireless tag of the plurality of wireless tags, and according to the The communication device outputs the identification information upon request.

According to such a configuration, each wireless tag can be accurately identified by the identification information stored in the wireless tag. The second embodiment of the present invention provides a wireless tag communication device, which has a plurality of wireless tags, and makes at least one first wireless tag in the plurality of wireless tags have a different directionality from other wireless tags. The wireless tag device communicates and forms relative motion with the wireless tag device, and the wireless tag communication device includes an antenna part and a control part. The antenna unit receives, from each wireless tag of the wireless tag device, identification information defined in advance that is different for each wireless tag. The control unit has a wireless tag device traveling direction/failure determination function for specifying a direction of relative motion with the wireless tag device or determining whether the wireless tag device is faulty or not based on the sequence or number of identification information obtained by the antenna unit.

According to such a configuration, it can be determined that some abnormality has occurred in the wireless tag device through the wireless tag device traveling direction/failure determination function.

The third embodiment of the present invention provides a wireless tag communication system, including a wireless tag device and a wireless tag communication device. The wireless tag device includes a plurality of tags, and a first member that makes at least one first wireless tag of the plurality of wireless tags have a directionality different from that of other wireless tags. The wireless tag communication device communicates with the wireless tag device and forms relative motion with the wireless tag device, and the wireless tag communication device includes an antenna part and a control part. The antenna unit receives, from each wireless tag of the wireless tag device, identification information defined in advance that is different for each wireless tag. The control unit has a wireless tag device traveling direction/failure determination function for specifying a direction of relative motion with the wireless tag device or determining whether the wireless tag device is faulty or not based on the sequence or number of identification information obtained by the antenna unit.

According to such a configuration, it is possible to make the wireless tag device robust against obstacles, and to suppress collisions of data output from the wireless tag device.

The fourth embodiment of the present invention provides a wireless tag device, and the wireless tag device includes a plurality of wireless tags. The plurality of wireless tags are installed at different positions in the direction of relative motion caused by movement of either or both of the wireless tag device and the wireless tag communication device communicating with the wireless tag device.

According to such a configuration, mutual interference of radio waves output from the respective wireless tags can be suppressed, and data collision can be suppressed.

A fifth embodiment of the present invention provides a wireless tag device, the wireless tag device has a plurality of wireless tags. In addition, at least one first wireless tag among the plurality of wireless tags is activated by receiving radio waves. In addition, the first wireless tag is placed at a position where the inquiry is received before other wireless tags are activated.

According to such a configuration, the first wireless tag can be read while avoiding data collision.

For a wireless tag device, in a possible implementation manner, there are multiple wireless tags and the first component. The first member changes the orientation of at least one first wireless tag among the plurality of wireless tags in a predetermined axial direction.

According to such a configuration, the first wireless tag can be read without data collision with other wireless tags.

For the wireless tag device, in a possible implementation manner, the plurality of wireless tags are set in such a way that the difference L between the reading start positions of the first wireless tag and the other wireless tags satisfies the following conditions, L>v×tq, wherein, v: in the direction of the relative motion formed by the movement of any device or both devices in the wireless tag device and the wireless tag communication device communicating with the wireless tag device The moving speed of , tq: the sending time interval of the inquiry based on the wireless tag communication device when the wireless tag is not in the range of the radio wave.

According to such a configuration, the first wireless tag can be read first without data collision.

The sixth embodiment of the present invention provides a wireless tag communication device, which communicates with a wireless tag device having a plurality of wireless tags with different orientations in a predetermined direction, and forms a wireless tag device in a predetermined direction. Relatively moving wireless tag communication device. This wireless tag communication device has an antenna unit and a control unit. The antenna unit receives previously defined identification information different for each wireless tag from each wireless tag of the wireless tag device. The control unit has a wireless tag device traveling direction/failure determination function for specifying the direction of relative motion with the wireless tag device or determining whether the wireless tag device is faulty or not based on the sequence or number of identification information obtained by the antenna unit.

According to such a structure, the reliability of reading a wireless tag can be improved.

Description of drawings

Next, a wireless tag device, a wireless tag communication device, and a wireless tag communication system according to the present invention will be described with reference to the drawings. A more complete and better understanding of the invention, and many of its attendant advantages, will readily be learned by reference to the following detailed description when considered in conjunction with the accompanying drawings, but the accompanying drawings illustrated herein are intended to provide a further understanding of the invention and constitute A part of the present application, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention, wherein:

FIG. 1 is a block diagram showing a configuration example of a wireless tag unit;

FIG. 2 is a block diagram showing a configuration example of a wireless tag communication device;

3 is a diagram showing an example of an internal configuration of a wireless tag communication unit;

4A to 4C are diagrams illustrating an example of a form when a wall member is used as the orientation changing member;

5A to 5C are diagrams illustrating an example of a form when a tilting member is used as the orientation changing member;

6A to 6C are diagrams illustrating an example of a form when a wall member is used as the orientation changing member;

7A to 7C are diagrams illustrating an example of a form when a tilting member is used as the orientation changing member;

8 is a diagram showing an example of a data format held by a wireless tag unit;

FIG. 9 is a diagram showing an example of a reading operation in a conventional configuration;

Fig. 10 is a diagram showing an example of the reading operation of the embodiment;

FIG. 11 is a diagram showing an example of the reading operation of the embodiment (multiple reading); and

FIG. 12 shows the relative speed of the wireless tag unit and the wireless tag communication device.

Explanation of reference signs

3 Directional change parts (first part)

11, 21 IC chip 16, 26 Tag antenna

31, 32, 35 Wall parts 33, 34, 36, 37 Inclined parts

100 wireless tag communication device 110 control unit

120 Wireless tag communication unit 121 Antenna

130 Notification section 140 Input section

150 Power Supply Unit 160 Host Communication Unit

200 upper equipment

500 Wireless Tag Communication System 801, 811 Processor

802, 812 storage unit

TG wireless tag unit (wireless tag device)

TG1, TG2 wireless tags

detailed description

Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the accompanying drawings. The same reference numbers in the figures indicate functionally identical or similar elements. While various aspects of the embodiments are shown in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or better than other embodiments.

In addition, in order to better illustrate the present invention, numerous specific details are given in the specific embodiments below. It will be understood by those skilled in the art that the present invention may be practiced without certain of the specific details. In some instances, methods, means, components and circuits well known to those skilled in the art have not been described in detail in order to highlight the gist of the present invention.

Next, the form of this embodiment will be described with reference to the drawings. In addition, the wireless tag unit and the wireless tag communication device exemplified in the embodiment have relative speeds as shown in FIG. 12 when either unit or device moves. As an example of this aspect, an example in which a wireless tag communication device is installed in advance in a mobile body such as a vehicle, and the wireless tag communication device reads each wireless tag unit at a passing point on a passage as the vehicle moves. In addition, another example of a reading scene with a relative speed can be given in which a wireless tag unit placed on a belt conveyor and traveling by rotating the belt conveyor can be read by a fixed wireless tag communication device. In addition to these, various application examples can be cited. In addition, the configurations in which both the wireless tag unit and the wireless tag communication device move to have relative speeds, and the configurations in which neither the wireless tag unit nor the wireless tag communication device moves can also be applied to the following embodiments.

FIG. 1 is a block diagram showing a configuration example of a wireless tag unit according to the embodiment. The wireless tag unit TG (wireless tag device) is arranged on items such as commodities and equipment, and on aisles, and is read by the wireless tag communication device 100 described later.

The wireless tag unit TG has two wireless tags of wireless tags TG1 and TG2. The wireless tag TG1 is the aforementioned RFID tag. The wireless tag TG1 has an IC chip 11 and a tag antenna 16 . The tag antenna 16 receives radio waves from a wireless tag communication device 100 described later. The IC chip 11 has a power supply unit 15 that obtains starting power from received radio waves, a tag storage unit 14 that stores identification information (tag ID) and the like, a tag wireless transmitter and receiver unit 13 that transmits and receives data from the tag storage unit 14, and controls the wireless tag. Label control unit 12 of the internal hardware of TG1.

The wireless tag TG2 also has the same configuration as the wireless tag TG1 and has an IC chip 21 and a tag antenna 26 . The IC chip 21 includes a tag control unit 22 , a tag wireless transmission and reception unit 23 , a tag storage unit 24 , and a power supply unit 25 similarly to the wireless tag TG1 described above. In addition, existing wireless tags may be used as the wireless tags TG1 and TG2.

The wireless tag unit TG has a directivity (directivity) changing means 3 . The directivity changing means 3 is for changing the relationship (orientation) between the direction and intensity of radio wave radiation of each of the wireless tags TG1, TG2 with respect to a predetermined axial direction. A specific example of the orientation changing means 3 will be described later.

FIG. 2 is a diagram illustrating an example of a wireless tag communication system according to an embodiment, and mainly shows an internal configuration of a wireless tag communication device. The wireless tag communication system 500 includes a plurality of wireless tag units TG and the wireless tag communication device 100 . Alternatively, the high-level device 200 may be included in the wireless tag system 500 . The wireless tag communication device 100 has a notification unit 130 and an input unit 140 . The notification unit 130 includes a display, a buzzer, and the like, and provides a screen for notifying the user of a situation and making settings. The input unit 140 is a member operated by the user, and may be a physical button or a touch panel disposed on the display of the notification unit 130 .

The wireless tag communication device 100 includes a power supply unit 150 that controls power supplied to the device, and a host communication unit 160 that provides communication means with the host device 200 . The power supply unit 150 may also be composed of a storage battery and a control circuit for charging and discharging the storage battery. In addition, when the wireless tag communication device 100 is installed on a moving object, it may include a control circuit that receives power from the moving object.

The wireless tag communication device 100 has a wireless tag communication unit 120 . The wireless tag communication unit 120 is connected to the antenna 121, communicates with the wireless tag unit TG, and receives the tag ID stored in each wireless tag TG1, TG2. The wireless tag communication unit 120 will be described in detail later.

The wireless tag communication device 100 has a control unit 110 . The control unit 110 is mainly composed of a processor 801 as an arithmetic processing device such as a CPU (Central Processing Unit: central processing unit). The control unit 110 controls the communication unit 130 , the input unit 140 , the power supply unit 150 , the host communication unit 160 , and the wireless tag communication unit 120 to control the whole wireless tag communication device 100 .

The control unit 110 has a storage unit 802 including a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM stores programs, setting data, and the like used by the control unit 110 in advance. Variable data is temporarily written in the RAM by the action of the control unit 110 . The RAM stores read information including identification information received by the wireless tag communication unit 120 , and the like. In addition, part or all of the control functions in the control unit 110 may be implemented in a circuit such as an ASIC (Application Specific Integrated Circuit: Application Specific Integrated Circuit).

The control unit 110 has a wireless tag device traveling direction/failure determination function 803 . This function will be described in detail later.

The high-level device 200 is a computer including at least a processor 811 and a storage unit 812 . Based on data such as a tag ID obtained from the wireless tag unit TG, the host device 200 acquires data such as position information corresponding to the data of the ID from a database, for example, and performs processing such as processing. In addition, the high-level device 200 may associate the data obtained from the wireless tag unit TG with the current time and the like, and accumulate them in the database. The communication between the high-level device 200 and the high-level communication unit 160 is performed by a conventionally used protocol regardless of wired or wireless. In addition, some of these operations on the high-level device 200 may be performed by other external servers.

FIG. 3 is a block diagram showing a specific configuration of the wireless tag communication unit 120 . The wireless tag communication unit 120 has a transmitting unit 502 for transmitting data to the wireless tag TG1 (the same goes for the wireless tag TG2), a receiving unit 501 for receiving data from the wireless tag TG1, a directional coupler 503 such as a circulator, and a low pass filter (LPF) 504 . The directional coupler 503 is connected to the transmitting unit 502 , the receiving unit 501 , and the low-pass filter 504 , and is connected to the antenna 121 through the low-pass filter 504 .

The transmission unit 502 has a coding unit (encoding unit) 511 , a PLL (Phase Locked Loop: Phase Locked Loop) unit 555 , an amplitude modulation unit 552 , a bandpass filter (BPF) 553 , and a power amplifier (Amp) 554 .

The coding unit 551 codes the transmission signal output from the transmission control unit 541 . The PLL unit 555 supplies the local carrier signal to the amplitude modulation unit 552 . The amplitude modulation unit 552 amplitude-modulates the local carrier signal from the PLL unit 555 with the transmission signal encoded by the encoding unit 551 . The bandpass filter 553 removes unnecessary components from the transmission signal amplitude-modulated by the amplitude modulation unit 552 . The power amplifier 554 amplifies the transmission signal that has passed through the bandpass filter 553 at an amplification factor corresponding to the transmission output setting signal from the transmission output setting unit 540 . Variable send output by amplifying the send signal. The transmission signal amplified by the power amplifier 554 is supplied to the directional coupler 503 .

Directional coupler 503 supplies the transmission signal from transmission unit 502 to antenna 121 through low-pass filter 504 . The transmission signal supplied to the antenna 121 is transmitted (radiated) from the antenna 121 as radio waves.

When radio waves radiated from the antenna 121 are received, the wireless tag TG1 is activated. Then, the activated wireless tag TG1 wirelessly transmits the information stored in the internal memory of the wireless tag TG1 to the wireless tag communication device 100 by performing backscatter modulation on the unmodulated signal. A wireless signal from the wireless tag TG1 is received through the antenna 121 .

When the antenna 121 receives a wireless signal from the wireless tag TG1 , the received signal is supplied from the antenna 121 to the directional coupler 503 through the low-pass filter 504 . The directional coupler 503 supplies the signal received by the antenna 121 , that is, the signal from the wireless tag TG1 , to the receiving unit 501 .

The receiving unit 501 has an I signal generating unit 561 , a Q signal generating unit 562 , an I signal processing unit 514 , a Q signal processing unit 563 , and a received signal potential detecting unit 527 .

The I signal generator 561 is composed of a first mixer 511 , a low-pass filter 512 and a binarization circuit 513 . The Q signal generator 562 is composed of a second mixer 519 , a low-pass filter 520 , a binarization circuit 521 , and a 90-degree phase shifter (phase shifter) 526 .

The receiving unit 501 inputs received signals from the directional coupler 503 to the first mixer 511 and the second mixer 519 , respectively. Furthermore, the receiving section 501 inputs the local carrier signal from the PLL section 555 to the first mixer 511 and the 90-degree phase shifter 526. The 90-degree phase shifter (phase shifter) 526 shifts the phase of the local carrier signal Phase shifted by 90 degrees, and supplied to the second mixer 519.

The first mixer 511 mixes the received signal and the local carrier signal to generate an I signal having an in-phase component with the local carrier signal. The I signal is supplied to a binarization circuit 513 through a low-pass filter 512 . The low-pass filter 512 removes unnecessary high-frequency components from the I signal and extracts symbolized data components. The binarization circuit 513 binarizes the signal that has passed through the low-pass filter 512 .

The second mixer 519 mixes the received signal and the local carrier signal that has been phase-shifted by 90 degrees, thereby generating a Q signal that is a quadrature component of the local carrier signal. The Q signal is supplied to a binarization circuit 521 through a low-pass filter 520 . The low-pass filter 520 removes unused high-frequency components from the Q signal and extracts symbolized data components. The binarization circuit 521 binarizes the signal that has passed through the low-pass filter 520 .

The I signal processing unit 514 includes an I signal synchronous clock generation unit 515 , an I signal preamble detection unit 516 , an I signal decoding unit 517 , and an I signal error detection unit 518 . The Q signal processing unit 563 includes a Q signal synchronization clock generation unit 522 , a Q signal preamble detection unit 523 , a Q signal decoding unit 524 , and a Q signal error detection unit 525 .

The reception unit 501 supplies the I signal binarized by the binarization circuit 513 of the I signal generation unit 561 to the I signal processing unit 514 . Furthermore, the Q signal generation unit 562 supplies the Q signal binarized by the binarization circuit 521 to the Q signal processing unit 563 . Here, the operations of the I signal processing unit 514 and the Q signal processing unit 563 are common. Therefore, the I signal processing unit 514 will be described below, and the description of the Q signal processing unit 563 will be omitted.

The I signal synchronous clock generation unit 515 always generates a clock signal synchronized with the binarized signal from the binarization circuit 513, and supplies the generated clock signal to the reception control unit 530, the I signal preamble detection unit 516, the I signal Signal decoding unit 517 and I signal error detection unit 518 .

The I signal preamble detector 516 detects the preamble added to the head of the I signal based on the clock signal from the I signal synchronous clock generator 515 . When a preamble is detected, the I-signal preamble detection unit 516 outputs a detection signal to the reception control unit 530 . When receiving the preamble detection signal, the reception control unit 530 supplies the I signal decoding unit 517 with a command signal to start decoding. The I signal decoding unit 517 samples the binarized signal from the binarization circuit 513 in synchronization with the clock signal from the I signal synchronous clock generation unit 515 . Then, when an instruction to start decoding is received from the reception control unit 530, the sampled binarized signal is decoded. The decoded data is supplied to the reception control unit 530 .

The reception control unit 530 supplies the decoded data to the I signal error detection unit 518 . The I signal error detection unit 518 detects the presence or absence of an error from the check code of the decoded data. Then, data indicating the detection result is supplied to the reception control unit 530 . The reception control unit 530 is configured to determine that the data has been received correctly when at least one of the I signal and the Q signal has no error. Accurately received reception data is stored in the storage unit 802 as read information under the control of the control unit 110 .

The received signal level (potential) detection unit 527 detects the amplitude of the I signal that has passed through the low-pass filter 512 and the amplitude of the Q signal that has passed through the band-pass filter 520 . Then, the value of the amplitude of the larger signal is notified to the reception control unit 530 as the reception signal potential. Alternatively, the vector-combined value (√{I2+Q2}) may be notified as the received signal level.

4A, 4B, and 4C to 7A, 7B, and 7C may be described as FIGS. 4 to 7 , respectively, below when no distinction is necessary.

Next, specific examples and comparative examples of the directivity changing means 3 included in the wireless tag unit TC will be described with reference to FIGS. 4 to 7 . 4A and 4B are diagrams in which a wall member that blocks radiation from a wireless tag is provided as the directivity changing member 3 . FIG. 4A is a top view of the wireless tag unit TG seen from above, and FIG. 4B is a side view of the wireless tag unit TG seen from the side. 4A and 4B show the traveling direction of the wireless tag communication device 100 with arrows. This traveling direction shows the direction of relative motion when both the wireless tag communication device 100 and the wireless tag unit TG move or one of them moves. In addition, FIG. 4B schematically shows the radio wave ranges of the wireless tags TG1 and TG2. In addition, the radio wave range here is shown as the relationship (directivity) between the radiation direction and the radiation intensity of the radio waves output from the wireless tags TG1 and TG2.

As shown in FIGS. 4A and 4B , the wireless tags TG1 and TG2 and the wall members 31 and 32 are arranged on the base member 40 . The arrangement positions of the wireless tag TG1 and the wireless tag TG2 are the same on the axis of the traveling direction (X-axis), and are different positions on the axis (Y-axis) perpendicular to the traveling direction. In addition, in the height direction (Z-axis direction), the positions of the wireless tag TG1 and the wireless tag TG2 match.

The wall member 31 is located on the downstream side of the wireless tag TG1 in the traveling direction. The wall member 32 is located on the upstream side of the wireless tag TG2 in the traveling direction. The wall members 31 and 32 are at mutually different positions in the Y-axis component. The wall member 31 corresponds to the wireless tag TG1 in the Y-axis component, and the wall member 32 corresponds to the wireless tag TG2 in the Y-axis component.

The wall member 31 has a function as a barrier for blocking radio waves output from the wireless tag TG1 in the axis of the traveling direction and narrowing the radio wave range on the side of the wall member 31 . The wall member 32 also functions as a barrier for blocking radio waves output from the wireless tag TG2 and narrowing the radio wave range on the side of the wall member 32 . Similarly, although not shown, the radio waves output from the wireless tag communication device 100 are also blocked by the wall members 31 and 32 . The wall members 31 and 32 reduce the range of the radio waves output from the wireless tags TG1 and TG2 on the wall member side, and as a result, have a directionality that deviates from the direction in which no wall members are provided.

FIG. 4C is a graph showing radio wave ranges of the wireless tags TG1 and TG2 when there are no wall members 31 and 32 , and is a graph for comparison with FIG. 4B . Since the wireless tags TG1 and TG2 in the traveling direction are at the same position, when there are no wall members 31 and 32 , the radio wave ranges of both in the traveling direction are basically the same as shown in FIG. 4C . As shown in FIG. 4B, by setting the wall members 31, 32 having a function as a barrier, the wireless tag TG1 has directionality on the left side of FIG. The downstream side of the direction) is directional. As shown in FIG. 4B , the reading start positions of the wireless tag TG1 and the wireless tag TG2 differ only by the distance L.

When the wall member 31 and the wall member 32 are installed, and the wireless tag communication device 100 moves and reads the wireless tag unit TG, as shown in FIGS. radio range. In this way, the wireless tag communication device 100 first reads the wireless tag TG1, and then reads the wireless tag TG2. According to this example, the wireless tag communication device 100 can shift the reading timing of the wireless tags TG1 and TG2 , and can read the wireless tags TG1 and TG2 without taking countermeasures such as collision avoidance.

The wall member 31 and the wall member 32 may be members as long as the transmittance of radio waves is not 100%. In addition, as in this example, both of the wall member 31 and the wall member 32 may be provided, or only one of them may be provided.

In addition, the distance from the wireless tag TG1 to the wall member 31 in the traveling direction, the distance from the wireless tag TG2 to the wall member 32, and the height of the wall members 31 and 32 in the Z-axis direction depend on the distance between the wireless tag TG1 and the wireless tag TG2. The size, shape, radio wave intensity, etc., or how much the radio wave range is different (how far the distance L is ensured) is designed. In addition, although the shape of the wall members 31 and 32 seen from the X axial direction is a rectangular shape in this Example, it is not limited to this. For example, a semicircular shape, a triangular shape, or the like may be selected as a suitable shape in terms of design.

Another embodiment and a comparative example of the orientation changing member 3 will be described with reference to FIG. 5 . FIG. 5A and FIG. FIG. 5A is a plan view of the wireless tag device TG seen from above, and FIG. 5B is a side view of the wireless tag device TG seen from the side. In addition, FIG. 5B schematically shows the radio wave range of each wireless tag.

The wireless tag unit TG shown in FIG. 5A and FIG. 5B has inclined members 33 and 34 on the base member 40, and wireless tags TG1 and TG2 are provided on the slopes of these inclined members. The respective positions of the wireless tag TG1 and the wireless tag TG2 are the same as the wireless tag unit TG shown in FIG. different locations.

The inclined member 33 has an inclined surface 331 as shown in FIG. 5B , and the wireless tag TG1 is set on the inclined surface 331 . The inclined member 34 has an inclined surface 34 as shown in FIG. 5B , and the wireless tag TG2 is set on the inclined surface 341 . The inclined surface 331 is inclined so as to become lower on the upstream side in the traveling direction and become higher as it goes downstream. Contrary to the inclined surface 331 , the inclined surface 341 is inclined so as to become higher on the upstream side in the traveling direction and become lower as it goes to the downstream side in the traveling direction. In this way, the inclined surface 331 and the inclined surface 341 form mutually opposite slopes.

FIG. 5C is a schematic diagram showing radio wave ranges of the wireless tags TG1 and TG2 when there are no tilting members 33 and 34 , and is a diagram for comparison with FIG. 5B . In this example, it is the same position as the wireless tag TG1 and the wireless tag TG2 in the traveling direction. Therefore, when there are no inclined members 33 and 34, the radio wave ranges in the traveling direction of the wireless tags TG1 and TG2 are substantially identical (see FIG. 5C ). As shown in FIG. 5B , by arranging the wireless tags TG1 and TG2 on different slopes, the directivity of the wireless tags can be made different. In this example, the reading times of the wireless tag TG1 and the wireless tag TG2 are also different, and the wireless tag TG1 is read first, and then the wireless tag TG2 is read. In this way, by making the reading time different, both tag IDs can be read without taking countermeasures such as collision avoidance.

In addition, as shown in FIGS. 5A and 5B , both of the inclined members 33 and 34 may be provided at the same time, or only one of them may be provided. In addition, in this example, although both inclined surfaces of the inclined members 33 and 34 are made to form mutually opposite slopes, the form is not limited to this.

In above-mentioned FIG. 4 and FIG. 5 , although the wireless tags TG1 and TG2 are arranged at the same position in the traveling direction, the case where the wireless tags TG1 and TG2 are arranged at different positions in the traveling direction will be described below. When each tag is installed at a different position in the traveling direction, only by this configuration, one wireless tag TG1 can be read first, and then the other wireless tag TG2 can be read. A configuration example will be described.

In the example shown in FIGS. 6A and 6B , a wall member 35 that blocks radiation from the wireless tags is provided between the wireless tags TG1 and TG2 . The wall member 35 blocks the radio waves output from the wireless tags TG1 and TG2 in the direction of the wall member 35 to narrow the range of the radio waves. Similarly, although not shown, radio waves output from the wireless tag communication device 100 are also blocked by the wall member 35 . By doing so, the orientation is biased toward the direction in which the wall member 35 is not provided. That is, as shown in FIG. 6B , the radio wave range of the wireless tag TG1 located upstream in the traveling direction is close to the upstream, and the radio wave range of the wireless tag TG2 located downstream in the traveling direction is close to the downstream.

FIG. 6C is a graph showing radio wave ranges of the wireless tags TG1 and TG2 when the wall member 35 is not provided, and is a graph for comparison with FIG. 6B . As shown in FIG. 6C , since the positions of the wireless tags TG1 and TG2 are already in different states on the axis of the traveling direction, their corresponding radio wave ranges are also different. In addition, as shown in FIG. 6B , by providing the wall member 35 between the wireless tag TG1 and the wireless tag TG2 , the orientation on the axis of the traveling direction can be further different.

In addition, the wall member 35 may be any member as long as the radio wave transmittance is not 100%. Dimensions such as height and width of the wall member 35, shape viewed from the X-axis direction, and installation position (between the wireless tag TG1 and the wireless tag TG2 or a position close to either tag, etc.) are determined according to the wireless tags TG1 and TG2. The strength of the radio wave, the size of the parts of the wireless tag, the extent to which the directionality is different, etc. are designed.

FIGS. 7A and 7B are diagrams showing a configuration in which the positions of the wireless tag TG1 and the wireless tag TG2 on the axis of the traveling direction are different, and the orientation is further different by using an inclined surface. 7A and 7B show an inclined member (slope) 36 having an inclined surface 361 forming a step and an inclined member (slope) 37 having an inclined surface 371 . As shown in FIG. 7B , the wireless tag TG1 located on the upstream side in the traveling direction is installed on an inclined surface 361 that is low on the upstream side and becomes high as it goes to the downstream side. Further, on the other hand, the wireless tag TG2 located on the downstream side in the traveling direction is installed on the inclined surface 371 that is high on the upstream side and becomes low as it goes downstream.

When reading the wireless tag unit TG shown in FIGS. 7A and 7B by the wireless tag communication device 100 relatively moving on the axis of the traveling direction, the wireless tag TG1 can be read first without taking countermeasures such as collision avoidance. Next, the wireless tag TG2 is read. With the inclined member 36, the orientation of the wireless tag TG1 is further on the upstream side with respect to the axis of the traveling direction as shown in FIG. 7B. The orientation of the wireless tag TG2 is further downstream with respect to the axis of the traveling direction by the inclined member 37 .

In addition, as shown in FIG. 7C , the object can be achieved only by arranging the wireless tag TG1 and the wireless tag TG2 at different positions with respect to the axis of the traveling direction. In addition, in this example, although both of the inclination members 36 and 37 were provided, the objective can be achieved even if either one of the inclination members 36 and 37 is provided.

The wireless tag unit TG shown in FIG. 6 and FIG. 7 includes wireless tags TG1 and Wireless Tag TG2. In this way, only by making the positions different from each other on the axis of the traveling direction, mutual interference of radio waves output from the individual wireless tags can be suppressed, and data collision can be suppressed.

Next, the format of the read data will be described with reference to FIG. 8 . The data shown in the upper row of FIG. 8 is already stored in the tag storage unit 14 of the wireless tag TG1, and the data shown in the lower row is already stored in the tag storage unit 24 of the wireless tag TG2. The "enterprise code" is a code for identifying a manufacturer. "Information about the place where the wireless tag is placed" is a code for identifying an article or the like on which the wireless tag is placed. For example, the "information about the place where the wireless tag is placed" is a code for designating a product category as well as a code for designating a position of a management point and the like. The "company code" and "information about the location where the wireless tag is placed" are common to the wireless tags TG1 and TG2. "Information indicating wireless tag TG1 (TG2)" is a code for uniquely identifying the wireless tag, and is different for each wireless tag.

9 to 11 show examples of operations when reading the data shown in FIG. 8 . First, FIG. 9 shows a timing chart with the horizontal axis as the time axis when a wireless tag unit not having the directivity changing means 3 is read. Here, an example of a protocol conforming to IS018000-6typeC, which is one of RFID standards, is shown, in which the number of slots per round is regarded as "2". In this example, consider one slot as 4 milliseconds. Therefore, in the case of FIG. 9 , one round is 8 milliseconds (4 milliseconds×2 time slots).

In FIG. 9 , symbols "Q", "RN", "A", and "ID" all indicate communication data, and a preamble symbol indicating the beginning of the data is included at the head of each communication data. In addition, each communication data includes an error detection symbol such as a CRC (Cyclic Redundancy Check: Cyclic Redundancy Check) symbol, and errors can be detected using the CRC symbol on the receiving side.

First, the wireless tag communication device 100 transmits a non-modulated carrier signal as a radio wave. The wireless tag TG1 and the wireless tag TG2 are activated in response to this radio wave. Each tag receives a non-modulated carrier signal at a predetermined time defined in the specification, and accumulates the carrier signal as output energy of radio waves.

Next, the wireless tag communication device 100 transmits a Query (query) command "Q" for instructing the start of the first round of reading. This Query command "Q" is output after the above-mentioned predetermined time elapses from the output of the non-modulated carrier signal (the tag starts to receive the non-modulated carrier signal). In addition, the time interval from the output of the Query command "Q" to the output of the next Query command "Q" can be arbitrarily designated and set corresponding to each wireless tag communication system 500, for example, according to the moving speed or the like. In addition, the Query command "Q" is output after 1 millisecond from the output of the Query command "Q", and the next Query command "Q" can also make the output time interval of the Query command "Q" arbitrarily different each time, for example, at 2 milliseconds Then output etc. For example, when the moving speed is low, the output time interval of the Query command "Q" can be extended, and the output time interval can be shortened as it becomes high speed, etc., so that the output time interval of the Query command "Q" can be changed according to the current moving speed composition.

The Query command "Q" in this example includes a parameter that regards the number of time slots in each round as "2". Each wireless tag generates a random number when receiving the Query command "Q". And, based on the random number, each radio tag TG1 , TG2 determines in which slot to respond among the two slots in one round. Moreover, each wireless tag TG1, TG2 generates response data "RN" similarly based on a random number. Since the response data "RN" includes a generated random number, it becomes a different value for each wireless tag. Furthermore, even the same wireless tag becomes a different value every time the random number is generated.

For example, there is no collision when the wireless tag TG1 responds in slot 0 and the wireless tag TG2 responds in slot 1, etc., when responding in different slots. On the other hand, as in the first round of FIG. 9 , when each wireless tag responds in the same time slot, a collision is performed. Thus, when there are two slots in the first round, the probability of collision is 1/2. When a collision occurs, the wireless tag communication device 100 cannot acquire information such as an ID from the wireless tag.

When time slot 0 in the first round ends, the wireless tag communication device 100 transmits "Q" to transition to the next time slot 1, but the wireless tags TG1 and TG2 can only reply once in a round. Therefore, the wireless tag does not reply in slot 1 of the first round.

In the next second round, since wireless tag TG1 selects time slot 0 and TG2 selects time slot 1, no conflict occurs. Therefore, the wireless tag communication device 100 can acquire identification information from each of the wireless tags TG1 and TG2.

When the response data "RN" from the wireless tag TG1 is received, the wireless tag communication device 100 transmits an Ack (acknowledgment) command "A" instructing that the response data "RN" is normally received. This Ack command "A" includes a random number of the response data "RN" received from the wireless tag TG1.

The wireless tag TG1 that has transmitted the response data "RN" waits for the Ack command "A". And, when receiving the Ack command "A", the wireless tag TG1 checks whether or not the random number of the response data "RN" transmitted by itself is included. When the random number generated by itself is included, the wireless tag TG1 recognizes the Ack command "A" as its own address. Upon receiving the Act command "A" of its own address, the wireless tag TG1 transmits the tag ID information "ID" stored in the tag storage unit 14 .

After transmitting the Ack command "A", the wireless tag communication device 100 waits for the tag ID information "ID". Then, when the tag ID information "ID" is received, whether there is an error is detected based on the CRC, and if there is no error, the received tag ID information "ID" is stored in the storage unit 802 as reception information.

As shown in time slot 0 of the first round, when wireless tags conforming to the IS018000-6typeC standard are activated at the same time, a collision often occurs and the wireless tags cannot be read. In order to avoid such collisions, the number of time slots in a round can also be increased, thereby reducing the probability of collisions. However, increasing the number of slots increases the number of unused slots (for example, slot 1 of the first round in FIG. 9 ), and correspondingly increases the time during which no communication occurs. From this, it can be seen that since increasing the number of slots may cause a time disadvantage, it is desirable to reduce the number of slots in a round.

Therefore, in this embodiment, the orientation changing means 3 described in Fig. 4A, Fig. 4B to Fig. The reading time of each wireless tag is different. Furthermore, since collisions can be avoided by providing the directivity changing means 3, the number of slots in a wheel can also be reduced. In FIG. 10, it is shown that when the orientation changing part 3 explained in FIG. 4A, FIG. 4B to FIG. 7A, and FIG. Sequence when the number of slots is set to "1".

The wireless tag communication device 100 is fixed from left to right on the axis of the traveling direction as described in FIG. 4 and the like. The directivity of the wireless tag TG1 is close to the left side of the axis (upstream side), and the directivity of the wireless tag 2 is close to the right side of the axis (downstream side). In this state, when the wireless tag communication device 100 moves down from the left side of the shaft to the right, the wireless tag TG1 first receives radio waves and starts up. When the wireless tag communication device 100 transmits "Q" before the wireless tag TG2 is activated, only the wireless tag TG1 responds and returns ID information in the slot 0 of the first round. Since the wireless tag TG1 has replied ID information, it is possible not to respond in the next round.

Next, when the wireless tag TG2 is activated in the second round, the wireless tag TG2 responds in the slot 0 of the second round and returns ID information. Also, no acknowledgment can be made in subsequent rounds. Although not shown in the figure, if it is assumed that it is not activated in the second round but is activated in the third round, a response is made in slot 0 of the third round.

In addition, the storage unit 802 of the wireless tag communication device 100 stores the information shown in FIG. 8 in advance, and includes the identification information of each wireless tag shown in FIG. 8 in the transmission data of the wireless tag TG1 and the wireless tag TG2. Furthermore, the wireless tag device is configured in such a way that the wireless tag TG1 can be read first when moving from left to right in FIG. 4 , for example. With the wireless tag device traveling direction/failure determination function 803, the traveling direction of the wireless tag communication device 100 (the direction of relative movement of the wireless tag unit and the wireless tag communication device 100) can be determined. That is, when the identification information of the wireless tag TG1 is read first and then the identification information of the wireless tag TG2 is read, it is known that the wireless tag communication device 100 has moved from left to right in FIG. 4 . On the other hand, when the identification information of the wireless tag TG1 is read after reading the identification information of the wireless tag TG2, it is known that the wireless tag communication device 100 has moved from right to left in FIG. 4 . Also, when the moving direction (for example, from left to right) is known in advance, the wireless tag device traveling direction/failure determination function 803 determines that there is no failure in the wireless tag device. In addition, when only the identification information of any one of the wireless tags TG1 and TG2 can be obtained, the wireless tag device traveling direction/failure determination function 803 of the wireless tag communication device 100 can also determine that a failure has occurred in the other wireless tag. . Alternatively, when the moving direction of the wireless tag communication device 100 is known in advance, such as when the wireless tag TG2 is read first and then the wireless tag TG1 is read when moving from left to right in FIG. 4 , the movement direction of the wireless tag communication device 100 The wireless tag device traveling direction/failure determination function 803 determines that some abnormality has occurred in the wireless tag device TG.

In addition, the traveling direction indicates the relative movement direction of the wireless tag communication device 100 and the wireless tag device TG.

The condition for performing the above operation is that the wireless tag TG1 receives radio waves to activate, and the wireless tag TG1 receives "Q" before the wireless tag TG2 activates. When expressing it in a formula, then L>v×tq, however,

L: difference between the reading start positions of the wireless tag TG1 and the wireless tag TG2 (illustrated in FIGS. 4 to 7 )

v: moving speed of the wireless tag communication device 100

tq: Query sending time interval when the wireless tag is out of radio range

If the above formula is satisfied, the wireless tag TG1 and the wireless tag TG2 can be read as in the reading sequence of FIG. 10 .

In addition, on the other hand, in order to improve the reliability of the tag ID read from the wireless tags TG1 and TG2, it can be determined as an authentic tag ID when it matches more than twice after reading a plurality of times. FIG. 11 shows the wireless communication procedure of the wireless tag communication device 100 of this example.

In the example of FIG. 11 , the control unit 110 of the wireless tag communication device 100 performs operation control so as to transmit an Ack command "A" immediately after receiving the tag ID. In the example of FIG. 11, the Ack command "A" is sent twice to obtain "ID" twice. When the two readings agree, the reliability of the read tag ID is high. Assume that when the read results are inconsistent, in this example issue the Ack command (A) again to read for the third time. When the third reading matches any one of the previous two times, the control unit 110 determines that the matching tag ID is a highly reliable tag ID. In this way, by continuously sending the Ack command "A" multiple times, it is possible to read the identification information multiple times in a short time.

"Communication" in this embodiment means that signals and data can be exchanged, and means the exchange of requests (commands) and responses (responses) between the wireless tag communication device and the wireless tag. In addition, a series of operations from the wireless tag communication device outputting the Query to the wireless tag outputting the information in the tag and the communication device receiving the information may be regarded as communication. In addition, although the state of carrier detection (sense) and the state of outputting an unmodulated carrier are not handled as communication in this embodiment, either state or both states of the two states may be included. inside as a communication.

In this embodiment, it is described as changing the directivity such as disposing the entire wireless tag (IC chip and tag antenna) on a slope, but since the directivity depends on the direction of the antenna, it is also possible to place only the tag antenna A composition that changes direction on an incline, etc. Regarding the case of installing the wall member, the wall member may be provided so as not to affect the entire wireless tag but only the tag antenna.

In this embodiment, the reading operation of the wireless tag communication device is described as an example of communication, but the above-described embodiments can also be applied to the data writing operation of the wireless tag communication device to the wireless tag.

In this embodiment, although a wireless tag unit (wireless tag device) including two wireless tags is described, the form is not limited to this, and a configuration including three or more wireless tags may be used. In addition, the wall members and inclined members described above with reference to FIGS. 4A and 4B to FIGS. 7A and 7B may be combined separately, and the orientation of the wireless tag may be changed by combining them.

As shown in FIG. 4A, FIG. 6B and FIG. 6A, FIG. 6B, the wall members 31, 32, 35 of the embodiment are arranged side by side with each wireless tag along the traveling direction (predetermined direction) and arranged facing the wireless tag. In addition, as shown in Fig. 5A, Fig. 5B and Fig. 7A, Fig. 7B, the inclined parts 33, 34, 36, 37 of the embodiment are inclined parts having slopes forming height differences in the direction of travel, and the wireless tags are set on the inclined planes. on the slope of the part.

As described in detail above, in the embodiment, even if a failure occurs in one wireless tag, data can be obtained from the other wireless tag. In addition, even if wireless tags using the same protocol or the same frequency are used in the wireless tag device, data collision between the individual wireless tags can be suppressed.

As described above, in the present invention, the wireless tag device is robust against obstacles and can suppress collisions of data output from the wireless tag device.

In the present invention, collision of radio waves output from the wireless tags can be avoided.

In the present invention, the radio wave output from the wireless tag has directivity deviated from a direction in which no wall member is provided.

In the present invention, the orientation of each wireless tag can be made different by providing the inclined member.

In the present invention, the first wireless tag can be read first without data collision.

In the present invention, each wireless tag can be accurately identified through the identification information stored in the wireless tag.

In the present invention, it can be determined that some abnormality has occurred in the wireless tag device by the wireless tag device traveling direction/failure determination function.

According to the present invention, it is possible to make the wireless tag device robust against obstacles, and to suppress collisions of data output from the wireless tag device.

In the present invention, it is possible to suppress mutual interference of radio waves output from individual wireless tags, and to suppress data collisions.

In the present invention, the first wireless tag can be read without data collision.

In the present invention, the first wireless tag can be read without data collision with other wireless tags.

In the present invention, the first wireless tag can be read first without data collision.

In the present invention, the reliability of reading a wireless tag can be improved.

The present invention can be implemented in various other forms as long as it does not deviate from its spirit or main characteristics. Therefore, all points of the above-mentioned embodiments are merely illustrations, and should not be interpreted limitedly. The scope of the present invention is shown by the claims and is not limited in any way by the text of the description. Moreover, all modifications, various improvements, substitutions and modifications belonging to the equivalent scope of the claims are within the protection scope of the present invention.

Claims (11)

1. A wireless tag device, comprising: multiple wireless tags; and The first component makes at least one first wireless tag among the plurality of wireless tags have a different directionality from other wireless tags. 2. The wireless tag device according to claim 1, wherein, The first member restricts a radiation direction of radio waves output from the wireless tag. 3. The wireless tag device according to claim 1 or 2, wherein, The first member is a wall member that blocks radiation from the wireless tag. 4. The wireless tag device according to any one of claims 1 to 3, wherein, The first part is an inclined part having a slope forming a height difference, The wireless tag is disposed on the inclined surface of the inclined member. 5. The wireless tag device according to any one of claims 1 to 4, wherein, The first member moves the first part in the direction of relative motion formed by the movement of either or both of the wireless tag device and the wireless tag communication device communicating with the wireless tag device. A wireless tag has a different directionality than other wireless tags. 6. The wireless tag device according to claim 5, wherein, Each wireless tag of the plurality of wireless tags stores at least different identification information corresponding to each wireless tag of the plurality of wireless tags, and outputs the identification information according to a request from the wireless tag communication device. 7. A wireless tag communication device for communicating with a wireless tag device having a plurality of wireless tags, and a first component that makes at least one first wireless tag of the plurality of wireless tags have a directionality different from other wireless tags And form relative movement with the wireless tag device, the wireless tag communication device includes: An antenna unit that receives, from each wireless tag of the wireless tag device, identification information that is different for each of the wireless tags and defined in advance; and The control unit has a wireless tag device that specifies a direction of relative motion with the wireless tag device or determines whether the wireless tag device is faulty or not, based on the order or the number of the identification information obtained by the antenna unit. Traveling direction/fault judgment function. 8. A wireless tag communication system, comprising: wireless tag device and wireless tag communication device, Among them, the wireless tag device includes: multiple wireless tags; and The first component makes at least one first wireless tag among the plurality of wireless tags have a different directionality from other wireless tags, The wireless tag communication device communicates with the wireless tag device and forms relative motion with the wireless tag communication device, the wireless tag communication device includes: An antenna unit that receives, from each wireless tag of the wireless tag device, identification information that is different for each of the wireless tags and defined in advance; and The control unit has a wireless tag device that specifies a direction of relative motion with the wireless tag device or determines whether the wireless tag device is faulty or not, based on the order or the number of the identification information obtained by the antenna unit. Traveling direction/fault judgment function. 9. A wireless tag device, the wireless tag device comprising: The plurality of wireless tags have different installation positions in a direction of relative motion caused by movement of either or both of the wireless tag device and a wireless tag communication device communicating with the wireless tag device. 10. A wireless tag device having a plurality of wireless tags, wherein, In the wireless tag device, at least one first wireless tag among the plurality of wireless tags is activated by receiving a radio wave, and the first wireless tag receives an inquiry before the other wireless tags are activated. A wireless tag. 11. The wireless tag device according to claim 10, wherein, The plurality of wireless tags are provided in such a manner that a difference L between reading start positions of the first wireless tag and the other wireless tags satisfies the following condition, L>v×tq, where, v: the moving speed in the direction of the relative motion formed by the movement of any device or both devices in the wireless tag device and the wireless tag communication device communicating with the wireless tag device, tq: the transmission time interval of the inquiry by the wireless tag communication device when the wireless tag is out of the radio wave range.