JP2005159533A - Communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system for accurately outputting response data from an information medium located in a prescribed region. <P>SOLUTION: In the communication system 1 disclosed herein, a reader provided with a management section 6 having a processing section 7 and an RF ID tag 2 make radio communication with each other. The processing section 7 includes: a transmission strength setting section 7a for setting a readable minimum transmission strength being a minimum strength of a transmission strength of an interrogation wave arriving in a border of a region A; and a discrimination section 7b for discriminating the RF ID tag 2 located in the region A on the basis of a reception state of a responding wave from the RF ID tag 2 in response to the interrogation wave transmitted with the readable minimum transmission strength. Thus, the communication system 1 can output only the response data of the RF ID tag 2 located in the region A on the basis of the discrimination result by the discrimination section 7a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides an information medium that transmits a response wave including identification information according to a received interrogation wave, and an antenna that transmits an interrogation wave to the information medium and receives a response wave from the information medium according to the interrogation wave The present invention relates to a communication system for performing wireless communication with a reading means provided.

  One of radio communication systems is an RFID (Radio Frequency Identification) system. The RFID system includes a reading device having a reading function, and an information medium that transmits various types of information such as identification information stored in accordance with instructions from the reading device. Some information media are in the form of cards or tags. Among these, tag-shaped information media are called RFID tags and are attached to management targets. In this RFID system, even when there are a plurality of RFID tags, the reader can access each RFID tag at one time. The RFID system implements various types of management for a management target by performing wireless communication between the RFID tag and the reader using radio waves.

  Here, the reading device transmits an interrogation wave, receives a response wave from the RFID tag corresponding to the interrogation wave, reads the RFID tag, and obtains response data of the RFID tag. However, the reading device may receive a response wave from an RFID tag located outside the reading area in addition to a response wave from the RFID tag located within the reading area that is the management range. In this case, when the response data of the RFID tag is output, the response data from the RFID tag located inside and outside the reading area is mixed, so that the management target located within the reading area may not be accurately managed. It was.

  For this reason, an RFID system has been proposed in which readers are arranged in a matrix in the reading region and the position of the RFID tag is detected by which reader the RFID tag is read (see Patent Document 1). This RFID system detects the position of the RFID tag, confirms the position of the RFID tag, outputs response data, and performs various types of management.

JP 07-56990 A

  However, the conventional RFID system has a problem in that the configuration of the RFID system is complicated because it is necessary to increase the number of readers distributed in a matrix in order to improve accuracy. In addition, when the transmission intensity of the interrogation wave of the reader changes, the RFID tag position cannot be confirmed accurately, and response data for the RFID tag outside the reading area may be output. There was a problem that the subject could not be managed smoothly.

  The present invention has been made in view of the above-described drawbacks of the prior art, and prevents output of response data from an information medium outside the reading area with a simple configuration, and from an RFID tag located within the reading area. An object of the present invention is to provide a communication system that accurately outputs the response data.

  The communication system according to claim 1 includes: an information medium that transmits a response wave including identification information according to a received interrogation wave; and the information medium that transmits the interrogation wave to the information medium and responds to the interrogation wave. In a communication system that performs wireless communication with a reading unit that includes an antenna that receives the response wave, a position within a predetermined reading area is set based on the reception state of the response wave with respect to the transmission intensity of the interrogation wave And determining means for determining the information medium to be performed.

  According to the communication system according to the present invention, by providing a determination unit, an information medium located in a preset reading area is determined based on a reception state of a response wave with respect to the transmission intensity of the interrogation wave. Only response data from the information medium determined to be located in the reading area based on the determination result can be output.

  The communication system according to claim 2 further includes transmission intensity setting means for setting a readable minimum transmission intensity that is a minimum intensity of the transmission intensity of the interrogation wave that reaches the boundary of the reading area, and the determination means includes the readable The information medium located in the reading area is determined based on a reception state at the antenna of the response wave transmitted by the information medium according to the interrogation wave having the minimum transmission intensity.

  The communication system according to claim 3, wherein the determination unit positions the information medium that has transmitted the response wave received by the antenna in the reading area in accordance with the interrogation wave having the readable minimum transmission intensity. The information medium is determined to be the information medium.

  According to a fourth aspect of the present invention, there is provided a communication system including a plurality of the antennas that transmit the interrogation wave from different directions with respect to the reading area.

  6. The communication system according to claim 5, wherein the transmission strength setting means sets the first readable minimum transmission strength and the second readable minimum transmission strength that is different from the first readable minimum transmission strength. The determination means selects the information medium that has transmitted the response wave received by the antenna for each of the readable minimum transmission intensities of the interrogation wave according to the information medium, and the first readable minimum The information medium corresponding to the transmission intensity is extracted as a determination target, the information medium corresponding to the second readable minimum transmission intensity is excluded from the determination target, and the remaining information medium is positioned in the reading area. The information medium is determined to be the information medium.

  The communication system according to claim 6, wherein the first readable minimum transmission intensity is a minimum intensity of transmission intensity at which the interrogation wave reaches a position that is a boundary of the reading area and is farthest from the antenna. The readable minimum transmission strength of 2 is the minimum transmission strength at which the interrogation wave reaches the position closest to the antenna at the boundary of the reading region, and the first readable minimum transmission strength and the second readable minimum transmission strength Correction data detection means for detecting, as correction data, a boundary minimum transmission intensity that is different from the readable minimum transmission intensity and that is the minimum intensity of the interrogation wave that reaches an arbitrary position on the boundary of the reading area. The antenna further comprises the first readable minimum transmission strength, the second readable minimum transmission strength, and the boundary minimum transmission strength corresponding to the correction data. And transmitting the waves.

  The communication system according to claim 7, wherein the determination unit compares the correction data with the transmission intensity of the interrogation wave according to the information medium that has transmitted the response wave, and is positioned in the reading area. The information medium to be determined is determined.

  The communication system according to claim 8, further comprising a boundary confirmation information medium that is arranged at an arbitrary position on the boundary of the reading area and transmits a confirmation response wave according to the interrogated wave that has arrived. The means adjusts the readable minimum transmission intensity based on a reception state of the confirmation response wave with respect to the interrogation wave transmitted with the readable minimum transmission intensity.

  The communication system according to claim 9 further includes a rejection information medium that is disposed at a boundary of an allowable area provided around the reading area and transmits a rejection response wave in response to the interrogated wave that has arrived, The transmission strength setting means adjusts the readable minimum transmission strength based on a reception state of the rejection response wave with respect to the interrogation wave transmitted with the readable minimum transmission strength.

  The communication system according to claim 10, wherein the transmission strength setting means decreases the readable minimum transmission strength when the response wave for rejection with respect to the interrogation wave transmitted with the readable minimum transmission strength is received. Features.

  The communication system according to an eleventh aspect of the present invention is further characterized by further comprising a blocking unit that electromagnetically blocks the interrogation wave and / or the response wave at least at a part of the boundary of the reading area.

  The communication system according to the present invention includes a determination unit that determines an information medium located in the reading area based on the reception state of the response wave with respect to the transmission intensity of the interrogation wave, thereby reading with a simple configuration and a simple processing procedure. Response data from the information medium located in the area can be output accurately. For this reason, it is possible to smoothly manage the information medium and the object to which the information medium is attached. In addition, the communication system according to the present invention performs wireless communication in a state where the boundary confirmation information medium and the rejection information medium are arranged at predetermined positions, and a response wave transmitted from the boundary confirmation information medium and the rejection information medium. The transmission intensity of the interrogation wave is adjusted based on the reception state of. For this reason, there exists an effect that a management object can be managed more correctly.

  Hereinafter, an RFID tag will be described as an example of an information medium for a communication system according to an embodiment of the present invention with reference to the drawings. Note that the present invention is not limited to the embodiments. In the description of the drawings, the same parts are denoted by the same reference numerals.

(Embodiment 1)
First, the communication system according to the first embodiment will be described. The communication system according to the first embodiment includes a determination unit that determines an RFID tag located in a reading area that is a management range using the fact that the arrival distance of the interrogation wave varies depending on the transmission intensity, and based on the determination result Only response data of the RFID tag located in the reading area is output. FIG. 1 is a block diagram illustrating a schematic configuration of the communication system according to the first embodiment. Note that the communication system according to the first embodiment includes an antenna that radially transmits an interrogation wave, and in the following description, the reading area is, for example, a circular area A for ease of explanation.

  As shown in FIG. 1, the communication system 1 according to the first embodiment includes an antenna control unit 5 that performs wireless communication between the RFID tag 2 and the antenna 4 and controls the operation of the antenna 4, and a management control unit 8. And a management unit 6 having a processing unit 7 and a memory 9, an operation unit 10 to which an operation instruction is input, and an output unit 11 for outputting response data of the RFID tag 2 as a reading device. The reading device transmits an interrogation wave from the antenna 4, receives a response wave from the RFID tag with respect to the interrogation wave by the antenna 4, reads the RFID tag 2, and obtains response data of the RFID tag 2. The management unit 8 is connected to a database 12 that stores information necessary for managing the management target. The area A is set in advance, and the communication system 1 outputs only response data of the RFID tag 2 located in the area A. For ease of explanation, it is assumed that the antenna 4 is disposed substantially at the center of the region A.

  The RFID tag 2 is attached to a management target, for example, and includes a storage unit, a control unit, and an antenna. The storage unit of the RFID tag 2 stores different identification information for each RFID tag 2, information on a management target, and the like. The RFID tag 2 operates by obtaining an operating power source from radio waves received from the antenna 4. When the RFID tag 2 receives an interrogation radio wave requesting a response transmitted by the antenna 4 (hereinafter referred to as “interrogation wave”), the control unit identifies information from the storage unit according to the interrogation wave. The antenna transmits a response radio wave (hereinafter referred to as “response wave”) including the extracted identification information and the like. The transmission / reception capability of the antenna of the RFID tag 2 is sufficient if it can be communicated with the antenna 4 when placed in the area A.

  The antenna 4 can transmit radio waves with different transmission intensities, and transmits an interrogation wave requesting a response to the RFID tag 2 with the transmission intensity set by the transmission intensity setting unit 7a of the processing unit 7. The antenna 4 receives the response wave from the RFID tag 2 with respect to the transmitted interrogation wave and outputs it to the antenna control unit 5.

  The antenna control unit 5 includes a control unit 5a and a transmission / reception unit 5b. The control unit 5a controls the operation of the antenna 4 and the transmission / reception unit 5b. The transmission / reception unit 5b converts the data to be transmitted into a query wave, converts the received response wave into response data in a predetermined format, and outputs the response data to the management unit 6. The response data includes identification information of the RFID tag 2 that has transmitted the response wave.

  The management unit 6 manages an instruction from the operation unit 10, response data from the RFID tag 2, and the antenna control unit 5. The processing unit 7 includes a transmission intensity setting unit 7a that sets a readable minimum transmission intensity that is the minimum intensity of the transmission distance of the interrogation wave that reaches the boundary of the area A as the transmission intensity of the interrogation wave transmitted by the antenna 4; And a determination unit 7b for determining the RFID tag located in the position. The transmission intensity setting unit 7a and the determination unit 7b operate according to a processing procedure described later. The management control unit 8 controls the antenna control unit 5, the processing unit 7, and the memory 9 in accordance with an input instruction or response data input, and outputs response data of the RFID tag determined to be located in the area A to the output unit 11 and Output to database 12. The memory 9 stores data to be transmitted / received and output in accordance with the operations of the processing unit 7 and the management control unit 8. In the communication system 1, the determination unit 7 b determines the RFID tag 2 located in the region A by using the arrival distance of the interrogation wave depending on the transmission intensity, and the RFID located in the region A based on the determination result Only the response data of tag 2 is output. For this reason, it becomes possible to accurately manage the management target to which the RFID tag 2 is attached.

  Next, a processing procedure in the communication system 1 until the response wave received by the antenna 4 is output as response data will be described. FIG. 2 is a flowchart showing a processing procedure until response data of the RFID tag 2 is output.

  First, as shown in FIG. 2, the area of the reading area is set (step S101), for example, the area A shown in FIG. 1 is set. Next, the transmission intensity setting unit 7a performs a query wave transmission intensity setting process for setting the transmission intensity of the interrogation wave of the antenna 4 (step S102). In this interrogation wave transmission intensity setting process, as will be described later, the transmission intensity of the interrogation wave from the antenna 4 is changed stepwise, and the readable minimum transmission intensity that is the minimum intensity of the transmission intensity of the interrogation wave that reaches the boundary of the region A Is set as the transmission intensity of the interrogation wave. Next, the antenna 4 transmits an interrogation wave with the set readable minimum transmission intensity (step S103), and the antenna 4 receives a response wave from the RFID tag 2 corresponding to the interrogation wave (step S104).

  And the determination part 7b performs the determination process which determines whether the RFID tag 2 which transmitted the response wave received by the antenna 4 is located in the area | region A using the response data output from the reading device ( Step S105). In this determination process, the determination unit 7b determines that the read RFID tag 2 is located in the area A. The readable minimum transmission intensity set in the interrogation wave transmission intensity setting process (step S103) is the minimum intensity of the transmission intensity of the interrogation wave that reaches the boundary of the region A. For this reason, when the interrogation wave is transmitted with the readable minimum transmission intensity, it is considered that the interrogation wave reaches the boundary of the area A and does not reach the outside of the area A. Therefore, the RFID tag 2 outside the area A cannot receive the interrogation wave and therefore does not transmit a response wave. From the above, since it is considered that the RFID tag 2 that has transmitted the response wave in response to the interrogation wave is limited to the RFID tag 2 located in the area A, all the read RFID tags 2 are included in the area A in the determination process. It can be determined that it is located.

  Then, the management control unit 8 outputs the response data of the RFID tag 2 determined to be located in the area A based on the determination of the determination unit 7b from the management unit 6 to the output unit 11 (step S106). If so, response data and the like are stored in the database 12.

  Next, the query wave transmission intensity setting process will be described. FIG. 3 is a flowchart showing a processing procedure until the interrogation wave transmission intensity setting processing is achieved. First, the setting RFID tag is registered (step S111). Here, the registration means that the identification information of the RFID tag is stored in the management unit 6, and the management unit 6 refers to the identification information in the input response data and the stored identification information, and The RFID tag 2 that has transmitted the response wave received by 4 is identified. In the interrogation wave transmission intensity setting process, the readable minimum transmission intensity is determined using the registered setting RFID tag.

  Next, the setting RFID tag is arranged at the boundary of the area A (step S112). For example, as shown in FIG. 4A, the setting RFID tag 2s is arranged at the boundary of the area A. Note that the setting RFID tag 2s may be disposed at any position as long as it is the boundary of the region A. This is because the area A has a circular shape and the antenna 4 is arranged at the approximate center of the area A.

Then, the transmission intensity setting unit 7a sets the transmission intensity stage n of the transmission intensity P _n to 1 which is an initial stage (step S113). The transmission intensity P ₁ whose transmission intensity stage is the initial stage 1 may be the minimum intensity of the transmission intensity of the antenna 4 or may be set in a timely manner according to the range of the region A and the reception state until then. The antenna 4 transmits the interrogation wave with the transmission intensity P ₁ (step S114), and when the antenna 4 cannot receive the response wave from the setting RFID tag 2s (step S115: No), FIG. Since the interrogation wave does not reach the setting RFID tag 2s as shown in FIG. 4, the interrogation wave transmission intensity level n is set to n + 1, that is, 2 (step S116), and the interrogation wave is transmitted again with the transmission intensity P ₂ ( Step S114). Then, the transmission intensity is increased by one step until the response wave from the setting RFID tag 2s can be received, and the interrogation wave is transmitted to the setting RFID tag 2s. The transmission strength stage may be the minimum interval of the transmission strength of the antenna 4 or may be set as appropriate according to the communication state up to that point.

As shown in FIG. 4B, when the interrogation wave transmitted with the transmission intensity _Pn reaches the setting RFID tag 2s, the RFID tag 2 transmits a response wave in response to the interrogation wave. For this reason, when the antenna 4 can receive the response wave of the setting RFID tag 2s (step S115: Yes), the interrogation wave has reached the boundary of the region A, so the transmission intensity setting unit 7a The transmission intensity P _{n at} that time is set as the interrogation wave transmission intensity (step S117). Here, the set interrogation wave transmission intensity is the minimum intensity of the transmission distance of the interrogation wave that reaches the boundary of the region A, and becomes the readable minimum transmission intensity. Then, the setting RFID tag 2s that has been arranged is removed, and the interrogation wave transmission intensity setting process ends. As shown in FIG. 3, the transmission intensity setting unit 7a gradually increases the transmission intensity of the interrogation wave, obtains a readable minimum transmission intensity that can read the setting RFID tag 2s arranged at the boundary of the area A, and sets it. To do.

  As described above, in the communication system 1 according to the first embodiment, the transmission intensity setting unit 7a sets the readable minimum transmission intensity, and transmits the response wave received by the antenna 4 according to the interrogation wave having the readable minimum transmission intensity. The RFID tag in which the RFID tag 2 is located in the area A is determined. Since the communication system 1 outputs only the response data of the RFID tag 2 located in the area A based on the determination result, and does not output the response data of the RFID tag 2 located outside the area A, the communication system 1 smoothly manages. The object can be managed.

  Moreover, the determination process of the determination means 7b determines the RFID tag 2 located in the area A by the simple processing procedure described above. Therefore, the communication system 1 can output response data with a simple processing procedure.

  Further, since the communication system 1 does not need to include a plurality of antennas 4 in the area A, it is possible to perform wireless communication with a simple device configuration. Further, the antenna 4 only transmits the interrogation wave with the readable minimum transmission intensity once for the response data output once. Thus, since it is not necessary to transmit the interrogation wave many times, it is considered possible to shorten the response data output time.

  The interrogation wave transmission intensity setting process does not need to be performed every time the RFID tag 2 is read. The interrogation wave transmission intensity setting process may be performed when performing wireless communication for the first time. Further, it may be performed once in a plurality of times of wireless communication, or may be performed periodically.

  Further, in the first embodiment, the case where the area A is circular and the antenna 4 is arranged at the substantially center thereof has been described, so that the arrangement position of the setting RFID tag 2s may be on the boundary of the area A. However, depending on the shape of the area A and the arrangement position of the antenna 4, the setting RFID tag 2s may be arranged at a position farthest from the antenna 4 on the boundary of the area A and the interrogation wave transmission intensity setting process may be performed. . By arranging the setting RFID tag 2s in this way and setting the readable minimum transmission intensity of the interrogation wave, it is determined that the RFID tag 2 is located in the area A regardless of the area A. Because.

(Embodiment 2)
Next, a communication system according to the second embodiment will be described. In Embodiment 1, a communication system including a reading device having a single antenna has been described. In Embodiment 2, a communication system including a reading device having a plurality of antennas will be described. For ease of explanation, the reading area will be described as a rectangular area B, for example.

  FIG. 5 is a block diagram of a schematic configuration of the communication system according to the second embodiment. As shown in FIG. 5, the communication system 21 according to the second embodiment includes an x-direction antenna 4a that transmits a query wave in the horizontal direction of the region B, that is, the x direction, and a query in the vertical direction of the region B, that is, the y direction. And a y-direction antenna 4b for transmitting waves. In addition, the processing unit 27 generates a region B from the response wave received by the transmission intensity setting unit 27a that sets the interrogation wave transmission intensity of the x direction antenna 4a and the y direction antenna 4b, and the x direction antenna 4a and the y direction antenna 4b. And a determination unit 27b for determining the RFID tag 2 located inside.

  Next, a processing procedure in the communication system 21 until response waves received by the x-direction antenna 4a and the y-direction antenna 4b are output as response data will be described. FIG. 6 is a flowchart showing a processing procedure until response data of the RFID tag 2 is output. As shown in FIG. 6, the reading area is set (step S201), for example, the area B shown in FIG. 5 is set. Next, the transmission intensity setting unit 27a performs a query wave transmission intensity setting process for setting the transmission intensity of the interrogation wave of the x direction antenna 4a and the y direction antenna 4b (step S202). In this interrogation wave transmission strength setting process, as will be described later, the maximum transmission strength and the minimum transmission strength of the transmission strength transmitted by the x-direction antenna 4a and the y-direction antenna 4b are set.

Next, the interrogation wave is transmitted from the x-direction antenna 4a with the transmission intensity P _x1 (step S203). This transmission strength P _x1 is the minimum transmission strength of the x-direction antenna 4a. Then, the response wave from the RFID tag 2 corresponding to the interrogation wave transmitted by the x-direction antenna 4a with the transmission intensity P _x1 is received (step S204). Next, the x-direction antenna 4a transmits an interrogation wave with the transmission intensity P _xn from the x-direction antenna 4a (step S205), and a response wave from the RFID tag 2 corresponding to the interrogation wave transmitted with the transmission intensity P _xn is sent. Receive (step S206). This transmission intensity P _xn is the maximum transmission intensity of the x-direction antenna 4a.

Then, the y-direction antenna 4b transmits the interrogation wave with the minimum transmission intensity P _y1 of the y-direction antenna 4b (step S207), and the response wave from the RFID tag 2 according to the interrogation wave transmitted with the transmission intensity P _y1 is transmitted. Receive (step S208). Then, the y-direction antenna 4b transmits the interrogation wave with the maximum transmission intensity P _ym of the y-direction antenna 4b (step S209), and the response wave from the RFID tag 2 according to the interrogation wave transmitted with this transmission intensity P _ym Receive (step S210). In addition to the response data received by each antenna, the transmission intensity of the interrogation wave corresponding to each RFID tag 2 is also stored in the memory 9.

  And the determination part 27b performs the determination process which discriminate | determines the RFID tag 2 located in the area | region B by the process sequence mentioned later (step S211). Then, the management control unit 8 performs data output for outputting the response data of the RFID tag 2 determined to be located in the region B based on the determination of the determination unit 27b from the management unit 6 to the output unit 11 (step S212). If necessary, the response data is stored in the database 12.

  Next, details of the query wave transmission intensity setting process will be described with reference to FIGS. FIG. 7 is a flowchart showing a processing procedure until the interrogation wave transmission intensity setting processing is achieved. FIG. 8 is a diagram for specifically explaining the interrogation wave transmission intensity setting process. In the interrogation wave transmission intensity setting process, the maximum transmission intensity and the minimum transmission intensity of the interrogation wave transmission intensity of the x-direction antenna 4a and the y-direction antenna 4b are set. First, the setting RFID tag is registered (step S221). Using this setting RFID tag, the transmission strength setting unit 27a detects the readable minimum transmission strength at a predetermined position, and sets the minimum transmission strength and the maximum transmission strength.

Then, in order to set the minimum transmission intensity of the x-direction antennas 4a, to place the set RFID tag to a position of the B ₁ shown in FIG. 8 (step S222). The interrogation waves transmitted from the antenna with the same transmission intensity reach a position that is substantially equidistant from the antenna, and the arrival position is substantially circular. For this reason, it is considered that the interrogation wave transmitted by the x-direction antenna 4a reaches any point on the curved line l ₁ that is an arc as shown in FIG. 8, for example. Here, B ₁ on the curve l ₁ shown in FIG. 8 is a on the boundary of the region B, and closest to the x-direction antenna 4a. Then, as in the first embodiment, by gradually increasing the transmit power of the interrogating wave, it detects a readable minimum transmission intensity in the x direction antenna 4a for the setting RFID tag disposed in the B ₁ (step S223 ). Then, the transmission strength setting unit 27a sets the readable minimum transmission strength detected in step S223 as the minimum transmission strength P _x1 of the x-direction antenna 4a (step S224). x-direction antenna 4a is, the case of transmitting the interrogating wave with the minimum transmission intensity P _x1, interrogating wave becomes possible to reach any position up to the curve l ₁ containing B _1, from x-direction antenna 4a than B ₁ It does not reach a distant position. For this reason, among the RFID tags 2 that have transmitted the response wave received by the x-direction antenna 4a, the RFID tag 2 that has transmitted the response wave in response to the interrogation wave transmitted with the minimum transmission intensity P _x1 is the boundary of the region B. and thus in a position close to the x-direction antenna 4a than the position B ₁ above.

Next, in order to set the maximum transmit power of the x-direction antennas 4a, to place the set RFID tag to a position of the B ₂ shown in FIG. 8 (step S225). This B ₂ is on the boundary of the region B and is located at the farthest distance from the x-direction antenna 4a. Then, as in the first embodiment, the transmission intensity of the interrogation wave is increased stepwise to detect the readable minimum transmission intensity of the x-direction antenna 4a (step S226), and the transmission intensity setting unit 27a detects in step S226. The readable minimum transmission intensity is set as the maximum transmission intensity P _xn of the x-direction antenna 4a (step S227). x-direction antenna 4a is, the case of transmitting the interrogating wave with the maximum transmit power P _xn, interrogation wave reaches at any position up to B _2, it does not reach the position away from the x-direction antenna 4a than B ₂ . Therefore, x-direction antenna 4a, the response wave from the RFID tag 2 is located away from the x-direction antenna 4a than B ₂ becomes not receive.

Next, similarly to the x-direction antenna 4a, the minimum transmission strength and the maximum transmission strength of the y-direction antenna 4b are set. To set the minimum transmission intensity in the y-direction antenna 4b, placing the set RFID tag to a position of the B ₃ shown in FIG. 8 (step S228). This B ₃ is on the boundary of the region B and is located at a distance closest to the y-direction antenna 4b. Then, similarly to the first embodiment, the transmission intensity of the interrogation wave is increased or decreased stepwise to detect the readable minimum transmission intensity of the y-direction antenna 4b (step S229), and the readable minimum transmission intensity detected in step S229 is determined as y. The minimum transmission intensity P _y1 of the directional antenna 4b is set (step S230). Next, in order to set the maximum transmit power in the y-direction antenna 4b, placing the set RFID tag to a position of the B ₄ illustrated in FIG. 8 (step S231). This B ₄ is on the boundary of the region B and is located at the farthest distance from the y-direction antenna 4b. Then, as in the first embodiment, the transmission intensity of the interrogation wave is increased or decreased stepwise to detect the readable minimum transmission intensity of the y-direction antenna 4b (step S232), and the readable minimum transmission intensity detected in step S232 is set to y. The maximum transmission intensity P _ym of the direction antenna 4b is set (step S233). Then, the setting RFID tag is removed, and the interrogation wave transmission intensity setting process ends.

  Next, details of the determination process will be described with reference to FIGS. 9, 10-1, and 10-2. FIG. 9 is a flowchart showing a processing procedure until the determination processing is achieved. 10A and 10B are diagrams for specifically explaining the determination process.

  First, the determination unit 27b refers to the identification information in each response data corresponding to the response wave received by the x-direction antenna 4a and the y-direction antenna 4b and the transmission intensity corresponding to the response wave to determine the RFID tag 2. Sorting is performed for each transmission intensity (step S241). In this determination processing, the RFID tag 2 in the region B is determined by extracting or excluding the RFID tag corresponding to each transmission intensity using the fact that the distance at which the interrogation wave reaches depends on the transmission intensity. .

Next, the determination unit 27b extracts the RFID tag 2 read with the transmission intensity P _xn as a determination target from the read RFID tag 2 (step S242). Interrogating wave transmitted by the transmission intensity P _xn, as shown in Figure 10-1, can reach up to the curve l _Pxn, located close to the x-direction antenna 4a than the curve l _Pxn this curve l _Pxn as a boundary Sent to. For this reason, the RFID tag 2 that can respond to the interrogation wave transmitted with the transmission intensity P _xn is the RFID tag 2 on the curve l _Pxn and the RFID tag 2 located closer to the x-direction antenna 4a than the curve l _Pxn. Yes, this RFID tag 2 is extracted as a determination target.

Then, the determination unit 27b excludes the RFID tag 2 read with the transmission intensity P _x1 from the determination target (step S243). In this case, as shown in FIG. 10A, the interrogation wave transmitted with the transmission intensity P _x1 reaches the curve l _Px1 . The RFID tag 2 that can respond to the transmission intensity P _x1 is the RFID tag 2 located in the region D and is located outside the region B. For this reason, by excluding the RFID tag 2 read with the transmission intensity P _x1 from the determination target (step S243), the RFID tag 2 located inside the region C shown in FIG. 10-1 remains as the determination target. It becomes.

Next, the determination unit 27b extracts the RFID tag 2 read with the transmission intensity P _ym from the determination target (step S244), and sets the extracted RFID tag 2 as the determination target. In this case, as shown in FIG. 10B, the interrogation wave transmitted with the transmission intensity P _ym reaches the curve l _Pym . The RFID tag 2 that can respond to the interrogation wave transmitted with the transmission intensity P _ym is the RFID tag 2 located closer to the y-direction antenna 4b than the curve l _Pym . Therefore, by extracting the RFID tag 2 from the remaining RFID tag 2, the RFID tag 2 located at a position away from the curve l _{Pym with} respect to the y-direction antenna 4b is excluded from the determination target.

Then, the determination unit 27b excludes the RFID tag 2 read with the transmission intensity P _y1 from the determination target (step S245). In this case, as shown in FIG. 10-2, the RFID tag 2 located in a region F that is a range closer to the y-direction antenna 4b than the curve l _Py1 to which the interrogation wave transmitted with the transmission intensity P _y1 arrives, Excluded from judgment. For this reason, the RFID tag 2 located in the area E shown in FIG. 10-2 remains as a determination target. For example, when the RFID tag 2a and the RFID tag 2b are read, the RFID tag 2b located in the area F is excluded from the determination target, and the RFID tag 2a located in the area E remains in the determination target.

  Then, the determination unit 27b determines that the RFID tag 2 remaining as a determination target is located in the region B (step S246). As illustrated in FIG. 10B, the RFID tag 2 remaining as a determination target is the RFID tag 2 located in the region E. The region E includes the region B, and although the shape of the boundary line between the region B and the region E may be different, the region B and the region E are considered to substantially match. For this reason, it is considered that it can be determined that the RFID tag 2 remaining as a determination target is located in the region B in step S246. Then, the determination unit 27b outputs the determination result to the management control unit 8, and the determination process ends.

  As described above, in the communication system 21 according to the second embodiment, the transmission strength setting unit 27a sets a plurality of readable minimum transmission strengths of the minimum transmission strength and the maximum transmission strength for each antenna. Then, the communication system 21 sorts the read RFID tags 2 according to the transmission intensity of the interrogation wave corresponding to the RFID tag 2, and the RFID tag 2 corresponding to the interrogation wave transmitted at the maximum transmission intensity is determined by the determination unit described above. The RFID tag 2 extracted as the determination target and transmitted with the minimum transmission intensity is excluded from the determination target, and it is determined that the remaining RFID tag 2 is located in the region B. For this reason, since the communication system 21 does not output the response data of the RFID tag 2b located outside the region B, but outputs only the response data of the RFID tag 2a located within the region B, the management target can be managed smoothly. be able to. Moreover, the determination process of the determination means 27b determines the RFID tag located in the area | region B with the simple process procedure mentioned above. For this reason, the communication system 21 can output response data with a simple processing procedure.

  In addition, since the communication system 21 according to the second embodiment does not need to include an antenna in the region B, it is possible to perform wireless communication with a simple device configuration. In addition, the interrogation waves transmitted by the x-direction antenna 4a and the y-direction antenna 4b are transmitted twice for each response data output. For this reason, since it is not necessary to transmit the interrogation wave many times, it is considered possible to shorten the output time of the response data.

  In the second embodiment, the case where the x-direction antenna 4a and the y-direction antenna 4b are provided and the response data of the RFID tag in the rectangular region B is output has been described. As shown in FIG. 4, a z-direction antenna 4c that transmits an interrogation wave from the z-direction may be further provided to output response data of an RFID tag located inside the region Q that is a three-dimensional region.

In this case, in the interrogation wave transmission intensity setting process, it is necessary to set the minimum transmission intensity P _z1 and the maximum transmission intensity P _zk for the z-direction antenna 4c as well as the x-direction antenna 4a and the y-direction antenna 4b. As illustrated in FIG. 12A, in the case of a region Qxz that is an arbitrary surface of the region Q in the xz direction, for example, when the z-direction antenna 4c transmits a query wave with the minimum transmission intensity P _z1 , the curve l _Pz1 The interrogation wave is transmitted to the z-direction antenna 4c side with 境界 as a boundary. When the z-direction antenna 4c transmits an interrogation wave with the maximum transmission intensity P _zk , the interrogation wave is transmitted to the z-direction antenna 4c side with the curve l _Pzk as a boundary. Further, as illustrated in FIG. 12B, in the case where the region Qyz which is an arbitrary surface of the region Q in the yz direction is taken as an example, a curve is obtained when the z-direction antenna 4c transmits the interrogation wave with the minimum transmission intensity P _z1 The interrogation wave is transmitted to the z-direction antenna 4c side with l _Pz1 as a boundary. When the z-direction antenna 4c transmits an interrogation wave with the maximum transmission intensity P _zk , the interrogation wave is transmitted to the z-direction antenna 4c side with the curve l _Pzk as a boundary.

In addition, after the interrogation wave transmission and the response wave reception between the x-direction antenna 4a and the y-direction antenna 4b are completed, the z-direction antenna 4c transmits the interrogation wave with the minimum transmission intensity P _z1 and the maximum transmission intensity P _zk in the z direction. The response wave for this interrogation wave is received. In the determination process, the RFID tag 2 located in the region is determined using the response wave reception result of the z-direction antenna 4c in addition to the response wave reception result of the x-direction antenna 4a and the y-direction antenna 4b. Cost. That is, in the determination process, after the RFID tag 2 read with the transmission strength P _y1 is excluded (step S245), the RFID tag 2 read by the z-direction antenna 4c with the maximum transmission strength P _zk from the remaining RFID tags 2. And the RFID tag 2 read by the z-direction antenna 4c with the minimum transmission intensity P _z1 is excluded from the extracted RFID tags 2, and the remaining RFID tag 2 is determined to be in the region Q.

  In addition to providing antennas at three locations, a plurality of antennas may be provided, an interrogation wave may be transmitted from the other direction, and an RFID tag located in the area may be determined using a reception result for the interrogation wave.

(Embodiment 3)
Next, a communication system according to the third embodiment will be described. In the third embodiment, an error between the set reading area and the actual reading area is reduced, and it is more accurately determined whether or not the RFID tag is positioned in the reading area.

  FIG. 13 is a block diagram of a schematic configuration of a communication system according to the third embodiment. As illustrated in FIG. 13, the communication system 31 according to the third embodiment includes a processing unit 37 including a correction data detection unit 37b in addition to the transmission intensity setting unit 27a and the determination unit 37c. The correction data detection unit 37b detects a boundary minimum transmission intensity, which will be described later, as correction data, and the determination unit 37c uses the correction data and the transmission intensity of the interrogation wave corresponding to the RFID tag 2 to identify the RFID tag. 2 is judged. In the third embodiment, the determination unit 37c uses the correction data detected by the correction data detection unit 37b to perform accurate region determination with reduced error for the RFID tag 2 located near the boundary of the region B. Is going.

  Next, a processing procedure in the communication system 31 until response waves received by the x-direction antenna 4a and the y-direction antenna 4b are output as response data will be described. FIG. 14 is a flowchart showing a processing procedure until response data of the RFID tag 2 is output. As shown in FIG. 14, the reading area is set (step S301), for example, the area B shown in FIG. 13 is set. Next, the transmission intensity setting unit 27a performs an interrogation wave transmission intensity setting process for setting the transmission intensity of the interrogation wave of the x direction antenna 4a and the y direction antenna 4b (step S302). In this interrogation wave transmission intensity setting process, the maximum transmission intensity and the minimum transmission intensity of the interrogation wave transmission intensity of the x-direction antenna 4a and the y-direction antenna 4b are followed according to the same processing procedure as the interrogation wave transmission intensity setting process of the second embodiment. And are set.

  Then, correction data detection processing for detecting correction data is performed (step S303). In the correction data detection process, correction data for reducing an error between the set reading area and the actual reading area is detected. The correction data detection unit 37b performs a processing procedure to be described later using the correction RFID tag, and detects the minimum transmission intensity for boundary corresponding to an arbitrary position on the boundary of the region B of the x direction antenna 4a and the y direction antenna 4b. And output to the memory 9 as correction data.

Next, interrogation wave transmission and response wave reception of the x-direction antenna 4a are performed (step S304). In this case, the x-direction antenna 4a adds the correction data detected in the correction data detection process (step S303) to the correction data detected in the correction data detection process (step S303) in addition to the minimum transmission intensity P _x1 and the maximum transmission intensity P _xn set in the interrogation wave transmission intensity setting process (step S302). The interrogation wave is transmitted with the corresponding minimum transmission intensity for the boundary. Then, interrogation wave transmission and response wave reception of the y-direction antenna 4b are performed (step S305). Similarly to step S304, the y-direction antenna 4b is detected by the correction data detection process (step S303) in addition to the minimum transmission intensity P _y1 and the maximum transmission intensity P _ym set by the interrogation wave transmission intensity setting process (step S302). The interrogation wave is transmitted with the minimum transmission intensity for the boundary corresponding to the correction data.

  Then, the determination unit 37c determines the transmission intensity of the interrogation wave and the correction data according to the RFID tag 2 from the RFID tags 2 read by the x-direction antenna 4a and the y-direction antenna 4b according to the processing procedure described later. A determination process for determining the RFID tag 2 located in the region B is performed (step S306). Then, the management control unit 8 performs data output for outputting the response data of the RFID tag 2 determined to be located in the region B based on the determination of the determination unit 37c from the management unit 6 to the output unit 11 (step S307). If necessary, the response data is stored in the database 12.

  Next, the correction data detection process will be described with reference to FIG. 15 and FIGS. 16-1 to 16-3. FIG. 15 is a flowchart showing a processing procedure until the correction data detection unit 37b achieves the correction data detection processing. 16A to 16C are diagrams for specifically explaining the correction data detection process. In the correction data detection process, in order to accurately determine whether or not an RFID tag in the vicinity of the boundary of the region B is located in the region B, the minimum transmission intensity for the boundary between the x-direction antenna 4a and the y-direction antenna 4b is corrected. Detect as data. The minimum transmission strength for boundary is the minimum strength of the transmission strength of the interrogation wave that reaches an arbitrary position on the boundary of the region B. The boundary minimum transmission strength is different from the minimum transmission strength and the maximum transmission strength set in step S302. In the determination process to be described later, for each RFID tag 2, the magnitude of the minimum transmission intensity for boundary, which is correction data, and the transmission intensity of the interrogation wave corresponding to the RFID tag 2 are compared. It is determined whether or not 2 is located.

  First, in the correction data detection process, a correction RFID tag is registered (step S321). The minimum readable transmission intensity of the x-direction antenna 4a and the y-direction antenna 4b for the correction RFID tag is detected and used as the minimum transmission intensity for the boundary.

Then, the correction RFID tag is arranged at an arbitrary position on the straight line l _L or the straight line l _R that is the boundary in the x direction of the region B (step S322). Next, the readable minimum transmission intensity (P _xH ) of the x-direction antenna 4a is detected by gradually increasing or decreasing the transmission intensity of the interrogation wave of the x-direction antenna 4a (step S323), and the interrogation wave of the y-direction antenna 4b is detected. The readable minimum transmission strength (P _yH ) of the y-direction antenna 4b with respect to the transmission strength P _xH is detected by increasing or decreasing the transmission strength in steps (step S324). Since the detected transmission strength P _xH and transmission strength P _yH are the minimum transmission strength for boundary with respect to an arbitrary position on the straight line l _L or the straight line l _R , the detected transmission strength P _xH and transmission strength P _yH are Is stored in the memory 9 as correction data (step S325).

The detection of the transmission intensity P _xH and the transmission intensity P _yH will be described with reference to FIGS. 16-1 and 16-2. First, the procedure for detecting the correction data on the straight line l _L will be described in detail, taking as an example the detection of the boundary minimum transmission intensity for L ₁ on the straight line l _L shown in FIG. Placing the correction RFID tag to a position L ₁ for detecting a correction data (step S322). Then, by increasing or decreasing the transmit power of the interrogating wave in the x-direction antenna 4a stepwise, to detect the readable minimum transmit power P _XHL1 the x-direction antenna 4a for correcting RFID tag located in L ₁ (step S323). The interrogation wave transmitted with the transmission intensity P _xHL1 is transmitted to the x-direction antenna 4a side with the curve l _PxHL1 shown in FIG. Next, the readable minimum transmission intensity P _yHL1 of the y-direction antenna 4b for the correction RFID tag located at L ₁ is detected (step S324). The transmission strength P _xHL1 and the transmission strength P _yHL1 are boundary minimum transmission strengths and are stored as correction data (step S325). The interrogation wave transmitted with the transmission intensity P _yHL1 is transmitted to the y-direction antenna 4b side with the curve l _PyHL1 shown in FIG. Further, as shown in Figure 16-1, sending a question wave readable minimum transmit power P _XHL1 the x-direction antenna 4a for L _1, in the straight line l _L, question wave L ₁ 'in addition to L ₁ is May reach. In this case, it is preferable to detect the readable minimum transmission strength P _yHL1 ′ of the y-direction antenna 4b for L ₁ ′ as the minimum transmission strength for the boundary. The interrogation wave transmitted with the transmission intensity P _yHL1 ′ is transmitted to the y-direction antenna 4b side with the curve l _PyHL1 ′ shown in FIG. In the determination process, together with the boundary for minimum transmission intensity _P xHL1, P yHL1, in order to perform the area determination using the value of the minimum transmission intensity for the boundary _P yHL1 '.

Next, the procedure for detecting the correction data on the straight line l _L will be specifically described by taking the correction data detection for R ₁ on the straight line l _R shown in FIG. 16-2 as an example. A correction RFID tag is arranged at a position R ₁ where correction data is detected (step S322). Then, by increasing or decreasing the transmit power of the interrogating wave stepwise, the readable minimum transmission intensity P _XHR1 the x-direction antenna 4a for correcting RFID tag located in R _1, readable minimum transmission intensity in the y-direction antenna _4b P yHR1 Is detected (step S323, step S324). The interrogation wave transmitted at the transmission intensity P _xHR1 is transmitted to the x-direction antenna 4a side with the curve l _PxHR1 shown in FIG. 14-2 as a boundary, and the interrogation wave transmitted at the transmission intensity P _yHR1 is illustrated in FIG. A curve l _PyHR1 shown is transmitted to the y-direction antenna 4b side as a boundary. The transmission strength P _xHR1 and the transmission strength P _yHR1 are the boundary minimum transmission strength, and are stored in the memory 9 as correction data (step S325). Similarly to the case shown in FIG. 16A, as shown in FIG. _16B , when the interrogation wave is transmitted with the readable minimum transmission intensity P _xHR1 of the x-direction antenna 4a for R ₁ , on the straight line l _R , in addition to the R ₁ there is a case in which questions wave to R ₁ 'is reached. In this case, it is preferable to detect the readable minimum transmission strength P _yHR1 ′ of the y-direction antenna 4b with respect to R ₁ ′ as the minimum transmission strength for the boundary. The interrogation wave transmitted at the transmission intensity P _yHR1 ′ is transmitted to the y-direction antenna 4b side with the curve l _PyHR1 ′ shown in FIG. In the determination process, together with the boundary for minimum transmission intensity _P xHR1, P yHR1, in order to perform the area determination using the value of the minimum transmission intensity for the boundary _P yHR1 '.

Then, it is determined whether or not the acquisition of the correction data on the straight line l _L and the straight line l _R is completed (step S326), and when it is determined that the acquisition of the correction data is not completed (step S326: No), the process proceeds to step S322. in step S322, to continue the acquisition of correction data on the straight line l _L on or linear l _R.

As described above, the correction RFID tag is arranged on the boundary of the region B, and the minimum readable transmission strength in the x direction and the minimum readable transmission strength in the y direction with respect to the readable minimum transmission strength in the x direction are used as the minimum transmission strength for the boundary. Detected and stored as correction data. By repeating this procedure, the memory 9 and a plurality of P _XHL value and P _XHR stored as P _XHL group or P _XHR group, memory P _YHL and P _YHR for each of these P _XHL and P _XHR also respectively Is done. As shown in FIG. 16C, on the boundary line of the region B, the readable minimum transmission intensity of the y-direction antenna 4b with respect to the readable minimum transmission intensity of the x-direction antenna 4a has only one value, L ₀ and R _0. It is preferable to detect the correction data at. This is because the correction data of L ₀ and R ₀ are also used in the determination process described later. Further, the detection of the readable minimum transmission strength (P _yH ) in the y-direction antenna 4b (step S324) may be performed prior to the detection of the readable minimum transmission strength (P _xH ) in the x-direction antenna 4a (step S323). . This is because even when step S324 is performed before step S323, the correction data can be detected.

Next, when the acquisition of the correction data on the straight line l _L and the straight line l _R is completed (step S326: Yes), the processing procedure similar to the detection of the correction data in the x direction described above is performed, and the region B Correction data on a straight line l _U or a straight line l _D , which is a boundary in the y direction. First, to place the correction RFID tag in a straight line l _U or on the straight line l _D is the y-direction of the boundary of the area B (step S327). Then, by increasing or decreasing the transmission intensity of the interrogation wave in steps, the readable minimum transmission intensity (P _ys ) of the y-direction antenna 4b and the readable minimum transmission intensity (P _xS ) of the x-direction antenna 4a with respect to the transmission intensity P _yS are obtained. It detects (step S328, step S329). The detected transmission strength P _xS and transmission strength P _yS are the minimum transmission strength for boundary, and are stored in the memory 9 as correction data (step S330). The memory 9 stores each P _ySU value detected by arranging the correction RFID tag on the straight line l _U as a P _ySU group, and detects it by arranging the correction RFID tag on the straight line _ID . P _ySD is stored as a P _ySD group. Then, _PySU and _PySD for these _PxSU and _PxSD are also stored in the memory 9, respectively.

Then, it is determined whether or not the correction data acquisition on the straight line l _U and the straight line _ID is completed (step S331). If the correction data acquisition is not completed (step S331: No), the process proceeds to step S328, and continues to acquire the correction data on the straight line l _U or on a straight line l _D. And when acquisition of correction data is complete | finished (step S331: Yes), a correction data detection process is complete | finished. As shown in FIG. 16C, on the boundary line of the region B, U ₀ , D ₀ has only one minimum boundary transmission strength of the y-direction antenna 4b with respect to the minimum boundary transmission strength of the x-direction antenna 4a. It is preferable to detect the correction data at. This is because the correction data of U ₀ and D ₀ are also used in the determination process described later. Further, the detection of the readable minimum transmission strength (P _xS ) in the x-direction antenna 4a (step S329) may be performed prior to the detection of the readable minimum transmission strength (P _yS ) in the y-direction antenna 4b (step S328). . This is because even when step S329 is performed before step S328, the correction data can be detected.

  Next, the procedure of the determination process will be described. In the determination processing, the RFID tag 2 located in the region B is determined based on the minimum transmission intensity for boundary in the correction data detected by the correction data detecting means and the transmission intensity of the interrogation wave corresponding to the RFID tag 2. Judgment. FIG. 17 is a flowchart showing a processing procedure until the determination processing is achieved.

First, similarly to the determination process in the second embodiment, the determination unit 37c transmits the identification information in the response data corresponding to the response wave received by the x-direction antenna 4a and the y-direction antenna 4b and the response wave. With reference to the strength, the RFID tag 2 is selected for each transmission strength (step S341). Then, the RFID tag 2 read with the transmission intensity P _xn is extracted as a determination target (step S342), and the RFID tag 2 read with the transmission intensity P _x1 is excluded from the determination target (step S343). Then, the RFID tag 2 read with the transmission strength P _ym is extracted from the determination target (step S344), and is determined as a determination target, and the RFID tag 2 read with the transmission strength P _y1 is excluded from the determination target (step S345). By performing Steps S341 to S345, the RFID tag 2 located in the region E in FIG. 10-2 is extracted. Then, by performing the following processing procedure, it is determined whether or not the RFID tag in the vicinity of the boundary of the region B is located in the region B, and the error of the region determination is reduced.

Next, to detect a transmission intensity P _y of the transmitted intensity P _x and y-direction antenna in the x-direction antenna 4a of the remaining RFID tag (step S346). In this case, among the transmission intensity of the interrogation wave RFID tag 2 according detects the lowest transmission intensity as a transmission strength P _x and transmit power P _y. Determination unit 37c, for each of the RFID tag 2, a determination by comparing the transmit power P _y of the transmitted intensity P _x and y-direction antenna 4b in the x-direction antennas 4a to RFID tag 2 in accordance with the corrected data. First, the transmission intensity P _x and the transmission intensity P _y of the RFID tag 2 to be examined coincide with the correction data of L ₀ , R ₀ , U ₀ , D ₀ on the boundary of the region B shown in FIG. It is determined whether or not to perform (step S347). If they match (step S347: Yes), the determination unit 37c determines that the RFID tag 2 is located in the region B (step S357). On the other hand, if they do not match, the process proceeds to step S348.

Next, it is determined whether or not the RFID tag 2 under consideration is located in the region B with the straight line l _L of the region B as a boundary. First, it is determined whether or not the transmission intensity P _x of the RFID tag 2 under consideration is a value included in the boundary minimum transmission intensity P _xHL group stored as correction data (step S348). If the transmission intensity P _x is included in the boundary minimum transmission intensity P _xHL group (step S348: Yes), the RFID tag 2 being considered is considered to be in the vicinity of the straight line l _L, so the next step Proceeding to S349, area determination is performed. For example, when the transmission intensity P _x of the RFID tag 2 _under consideration matches the boundary minimum transmission intensity P _xHL1 , the interrogation wave transmitted with the transmission intensity P _x is as shown in FIG. This is because the interrogation wave may be transmitted to the RFID tag 2 that is transmitted to the position of the curve l _PxHL1 and located outside the straight line l _L that is the boundary of the region B.

When the transmission strength P _x is included in the boundary minimum transmission strength P _xHL group (step S348: Yes), the transmission strength P _y of the RFID tag 2 under consideration is P _yHL ′ <P _y <P. It is determined whether it is _yHL (step S349). P _yHL and P _yHL ′ are the minimum transmission strength for boundary corresponding to the minimum transmission strength P _xHL for boundary that matches the transmission strength P _x . If P _yHL ′ <P _y <P _yHL (step _S349 : Yes), the determination unit 37c determines that the RFID tag 2 is not located in the region B (step S350). When the transmission intensity P _y of the y-direction antenna 4b is P _yHL1 ′ <P _y <P _yHL1 , the interrogation wave transmitted with the transmission intensity P _y is a curve l _PyHL1 and a curve l _PyHL1 ′ shown in FIG. Sent between and. Further, when the transmission intensity P _x of the x-direction antenna 4a is the boundary minimum transmission intensity P _xHL1 , the RFID tag 2 corresponding to the interrogation wave transmitted with such transmission intensity has the curves l _PxHL1 and l _PyHL1 . This is because it is located in the region G surrounded by the curve l _PyHL1 ′ and the straight line l _L and is not considered to be located in the region B. On the other hand, if P _yHL ′ <P _y <P _yHL is not satisfied (step _S349 : No), the process proceeds to step S351 to perform the next examination.

Next, it is determined whether or not the RFID tag 2 under consideration is located in the region B with the straight line l _R of the region B as a boundary. When the transmission intensity P _x of the RFID tag 2 under consideration is not included in the boundary minimum transmission intensity P _xHL group (step _S348 : No) and when P _yHL ′ <Py <P _yHL is not satisfied (step S349: No), it is determined whether or not the transmission intensity P _x is included in the boundary minimum transmission intensity P _xHR group stored as correction data (step S351). If the transmission intensity P _x is included in the boundary minimum transmission intensity P _xHR group (step S351: Yes), the RFID tag 2 under consideration is considered to be in the vicinity of the straight line l _R, so the next step Proceeding to S352, area determination is performed. For example, when the transmission intensity P _x of the RFID tag 2 _under consideration matches the minimum transmission intensity P _xHR1 for the boundary, as shown in FIG. 14-2, the interrogation wave transmitted with the transmission intensity P _x is This is because the interrogation wave may be transmitted to the RFID tag 2 that is transmitted to the position of the curve l _PxHR1 and located outside the straight line l _R that is the boundary of the region B.

When the transmission strength P _x is included in the boundary minimum transmission strength P _xHR group (step S351: Yes), the transmission strength P _{y of the} RFID tag under consideration is P _y <P _yHR ′ or P _yHR. <determines whether the P _y (step S352). P _yHR and P _yHR ′ are boundary minimum transmission strengths corresponding to the boundary minimum transmission strength P _xHR that matches the transmission strength P _x . Determining unit 37c sets, when _{P y} <P yHR 'or _P yHR <P _y: determining (step S352 Yes), the RFID tag 2 is not located within the area B (step S350). If the transmit power P _y in the y-direction antenna 4b is _{P y} <P yRL1 ', _y-direction than the curve l _PyHR1 interrogating wave transmitted by the transmission intensity P _y is a curve l _PyHR1 shown in Figure 14-1 as a boundary It is transmitted to a region away from the antenna 4b. When P _yHR1 <P _y , the interrogation wave transmitted with the transmission intensity P _y is transmitted to the y-direction antenna 4b side with the curve l _PyHR1 ′ as a boundary. Further, when the transmission intensity P _x of the x-direction antenna 4a is the boundary minimum transmission intensity P _xRL1 , the RFID tag 2 corresponding to the interrogation wave transmitted with such transmission intensity has a curve l _PyHR1 and a straight line _lL. This is because it is located in the area H or the area H ′ in contact with the area H or the curve l _PyHL1 ′ and the straight line l _L and is not considered to be located in the area B. On the other hand, if P _y <P _HR ′ or P _HR <P _y is not satisfied (step S352: No), the region determination with the straight line l _L and the straight line l _R in the region B as a boundary ends, and the following examination is performed. To do so, go to step S353.

Then, RFID tag 2 being considered determines whether or not located in the area B on the straight line l _U region B as a boundary. If the transmission intensity P _x of the RFID tag 2 being considered is not in the minimum transmission intensity P _XHR group for boundary (step S351: No) and P _y <If not P _YHR 'or _P yHR <P _y is (step S352: No), transmission strength P _y to determine whether or not included in the minimum transmission intensity P _YSU group for boundary (step S353). If the transmission strength P _y is included in the boundary minimum transmission strength P _ySU group (step S353: Yes), the RFID tag 2 under consideration is considered to be in the vicinity of the straight line l _U, so the next step _Proceeding to S354, it is determined whether or not the transmission intensity P _x is P _xSU ′ <P _x <P _xSU (step S354). P _xSU and P _xSU ′ are the minimum transmission strength for boundary corresponding to the minimum transmission strength P _ySU for boundary that matches the transmission strength P _y . When the transmission intensity P _{x of the} RFID tag under consideration is P _xSU ′ <P _x <P _xSU (step S354: Yes), the determination unit 37c determines that the RFID tag 2 is not located in the region B. (Step S350). On the other hand, if P _xSU ′ <P _x <P _xSU is not satisfied (step S354: No), the process proceeds to step S355 to perform the next examination.

Next, it is determined whether or not the RFID tag 2 under consideration is located in the region B with the straight line _{ID in the} region B as a boundary. If the transmission intensity P _y of the RFID tag 2 being considered is not in the minimum transmission intensity P _YSU group for boundary (step S353: No) and P _XSU '<If not _{P x} <P xSU (step S354 : No), transmission strength P _y to determine whether or not included in the minimum transmission intensity P _YSD group for boundary (step S355). If the transmission strength P _y is included in the minimum transmission intensity P _YSD group for boundary (step S355: Yes), since the RFID tag 2 is considered to be in the vicinity of the straight line l _D being considered, the next step Proceeding to S356, area determination is performed. If the transmission strength P _y is included in the minimum transmission intensity P _YHD group for boundary (step S355: Yes), the transmit power P _x of the RFID tag 2 being considered, P _x <P _xsd 'or P _xSD <to determine whether it is P _x (step S356). P _xSD and P _xSD ′ are the minimum boundary transmission strength corresponding to the minimum transmission strength P _ySD for boundary that matches the transmission strength P _y . When the transmission intensity P _{x of the} RFID tag under consideration is P _x <P _xSD ′ or P _xSD <P _x (step S356: Yes), the determination unit 37c determines that the RFID tag 2 is located in the region B. It is determined not to be performed (step S350).

On the other hand, if P _x <P _xSD ′ or P _xSU <P _x is not satisfied (step S356: No), it is determined that the RFID tag 2 is located in the region B (step S357). Further, when the transmission strength P _y is not included in the minimum transmission intensity P _YSD group for boundary (step S355: No), the RFID tag 2 is determined to be positioned in the area B (step S357). This is because the examination as to whether or not it is located within the region B with respect to all the boundaries of the region B has been completed.

  Then, it is determined whether or not the examination of the transmission strength of the RFID tag 2 has been completed (step S358). If it is determined that the examination has not been completed (step S358: No), the process returns to step S346 to examine other RFID tags 2. I do. When the examination of the transmission intensity of the RFID tag 2 is completed (step S358: Yes), the determination unit 37c outputs the determination result to the management control unit 8, and the determination process ends.

  As described above, in the communication system 31 according to the third embodiment, the determination unit 37c uses the correction data detected by the correction data detection unit 37b and the transmission intensity of the interrogation wave according to the RFID tag 2 to use the RFID tag. It is determined whether or not it is located in the area B every two. For this reason, compared with Embodiment 2, the error of the area | region determination with respect to the RFID tag 2 located in the boundary vicinity of the area | region B can be reduced. Accordingly, the communication system 31 does not output the response data of the RFID tag 2 located in the vicinity of the boundary of the region B and outside the region B, and more accurately outputs the response data of the RFID tag 2 positioned in the region B. Can be managed smoothly.

  In addition, the determination unit 37c determines the RFID tag 2 located in the region B by comparing the minimum transmission intensity for boundary, which is correction data, with the transmission intensity of the interrogation wave corresponding to the RFID tag 2. Therefore, a complicated processing procedure is not required. Therefore, in the third embodiment, accurate area determination can be performed with a simple processing procedure.

  In addition, since the communication system 31 according to the third embodiment does not need to include an antenna in the area B, it is possible to perform wireless communication with a simple device configuration. Further, the x-direction antenna 4a and the y-direction antenna 4b transmit the interrogation wave with the minimum transmission strength for the boundary corresponding to the correction data in addition to the minimum transmission strength and the maximum transmission strength with respect to the output of the response data once. Only. For this reason, since the number of times the interrogation wave is transmitted is small compared to the case where the interrogation wave is transmitted many times at a fine transmission intensity stage for the entire region B, it is possible to shorten the response data output time. It is believed that there is.

  In the third embodiment, the correction data detection process has been described by taking one point on each boundary as an example. However, by detecting as many correction data as possible, the actual reading area and the set reading area can be detected. The error can be further reduced.

  In the third embodiment, the communication system 31 provided with the x-direction antenna 4a and the y-direction antenna 4b has been described. However, the communication system 31 is not limited thereto, and further includes a z-direction antenna 4c that transmits a query wave in the z direction. It is good also as a communication system which outputs the response data of the RFID tag 2 located inside the area | region Q which is a three-dimensional area | region. In this case, in the correction data detection process, it is necessary to detect the correction data for the boundary corresponding to the z direction of the three-dimensional region as in the above-described processing procedure, and in the determination process, in addition to the correction data in the x direction and the y direction. , Z correction data is also used to determine whether or not it is located within the region. In addition to providing antennas at three locations, a plurality of antennas are provided, correction data is detected for each region boundary in the direction in which the antenna transmits an interrogation wave, and RFID located within the region using the correction data and response data The tag 2 may be determined.

(Embodiment 4)
Next, a communication system according to the fourth embodiment will be described. In the fourth embodiment, wireless communication between the RFID tag and the antenna is performed in a state where the boundary RFID tag is arranged at the boundary of the reading area.

  First, in the communication system according to the fourth embodiment, a case where a single antenna that transmits a query wave radially is provided will be described. FIG. 18 is a diagram for explaining the arrangement of RFID tags in the communication system according to the fourth embodiment. The communication system according to the fourth embodiment has a configuration equivalent to that of the communication system 1 shown in FIG. Then, as shown in FIG. 18, the RFID tag 2 is read in a state where the boundary RFID tag 42 a that is a boundary confirmation RFID tag is arranged at the boundary of the region A. In the fourth embodiment, every time wireless communication is performed based on the reception state of the response wave for confirmation from the boundary RFID tag 42a, the reduction of the transmission intensity of the interrogation wave of the antenna 4 is adjusted so that the RFID tag 2 is in the area A. It is determined whether or not it is located.

  Next, a processing procedure until the response wave received by the antenna 4 is output as response data when the boundary RFID tag 42a is arranged as shown in FIG. 18 will be described. FIG. 19 is a flowchart showing a processing procedure until response data of the RFID tag 2 is output. As shown in FIG. 19, the reading area is set (step S401), and for example, the area A shown in FIG. 18 is set. Next, a query wave transmission intensity setting process is performed according to the same processing procedure as the query wave transmission intensity setting process of the first embodiment (step S402). Then, the boundary RFID tag 42a is registered (step S403), and the boundary RFID tag 42a is arranged (step S404). As shown in FIG. 18, the boundary RFID tag 42a is arranged at the boundary of the area A, and the number of boundary RFID tags 42a to be arranged may be one or more. As will be described later, when a response wave for confirmation is received from the boundary RFID tag 42a corresponding to the interrogation wave transmitted with the readable minimum transmission intensity, it is determined whether or not the read RFID tag 2 is located in the area A. Do.

  Next, the antenna 4 performs interrogation wave transmission and response wave reception (step S405). The determination unit 7b determines whether or not all the boundary RFID tags 42a arranged at the boundary are read from the received response data (step S406). When all the boundary RFID tags 42a are not read (step S406). S406: No), it is considered that the transmission intensity of the antenna 4 decreases and the interrogation wave does not reach the entire area A. If all the boundary RFID tags 42a have not been read (step S406: No), the transmission intensity setting unit 7a adjusts the interrogation wave transmission intensity (step S407), and sets the adjusted transmission intensity as the readable minimum transmission intensity. . Then, the antenna 4 transmits the interrogation wave again with the readable minimum transmission intensity, and receives a response wave corresponding to the interrogation wave (step S405). These steps S405 to S407 are repeated until all the confirmation response waves from the boundary RFID tag 42a are received, and the transmission intensity setting unit 7a adjusts the readable minimum transmission intensity so that the confirmation response waves can be received.

  If all of the boundary RFID tags 42a can be read (step S406: Yes), it is considered that the interrogation wave transmitted by the antenna 4 with the readable minimum transmission intensity reaches the boundary of the region A. The determination unit 7b determines that the RFID tag 2 read together with all the boundary RFID tags 42a is located in the area A (step S408). When the interrogation wave is transmitted with the transmission intensity at which the antenna 4 can read the boundary RFID tag 42a, for example, the interrogation wave reaches the RFID tag 2a inside the boundary of the region A. The response wave from can be received. On the other hand, since the interrogation wave does not reach the RFID tag 2b outside the boundary of the region A, the RFID tag 2b does not transmit a response wave. For this reason, it is considered that the read RFID tag 2 does not include the RFID tag 2b outside the boundary of the region A.

  Then, the determination unit 7b outputs the determination result to the management control unit 8, and the management control unit 8 stores the response data of the RFID tag 2 determined to be located in the area A based on the determination of the determination unit 7b. 6 outputs data to the output unit 11 (step S409), and stores the response data in the database 12 if necessary.

  As described above, in the fourth embodiment, the boundary RFDI tag 42a is arranged on the boundary of the region A, and the interrogation wave of the antenna 4 is determined depending on whether or not the response wave for confirmation is received from the boundary RFID tag 42a every time wireless communication is performed. Judgment on decrease in transmission strength. When the transmission intensity of the interrogation wave of the antenna 4 is reduced, the transmission intensity of the interrogation wave of the antenna 4 is adjusted until all the boundary RFID tags 42a can be read, and the interrogation wave is reliably transmitted to the boundary of the area A. Is reaching. Therefore, since the transmission intensity of the interrogation wave of the antenna 4 is optimized each time wireless communication is performed, it can be more reliably determined whether or not the read RFID tag 2 is located within the boundary A.

  Next, a communication system capable of accurately determining the RFID tag 2 located in the area A even when the transmission intensity of the interrogation wave of the antenna 4 fluctuates and increases will be described. FIG. 20 is a diagram for explaining another example of the arrangement of RFID tags in the communication system according to the fourth embodiment. In this case, as shown in FIG. 20, the boundary RFID tag 42a is disposed at the boundary of the region A, and the rejection RFID tag 43a is disposed at the boundary of the allowable region J provided around the region A. Reading is in progress. In this communication system, the transmission intensity of the interrogation wave of the antenna 4 is adjusted each time wireless communication is performed based on the reception state of the confirmation response wave from the boundary RFID tag 42a and the rejection response wave from the rejection RFID tag 43a. As shown, it is determined whether or not the RFID tag 2 is located in the area A.

  Next, a processing procedure until the response wave received by the antenna 4 is output as response data when the boundary RFID tag 42a and the rejection RFID tag 43a are arranged as shown in FIG. 20 will be described. FIG. 21 is a flowchart showing a processing procedure until response data of the RFID tag 2a is output when the boundary RDID tag 42a and the rejection RDID tag 43a are arranged as shown in FIG.

  First, as shown in FIG. 21, region A and allowable region J are set (step S421). Next, a query wave transmission intensity setting process is performed according to the same processing procedure as the query wave transmission intensity setting process of the first embodiment (step S422). Then, the boundary RFID tag 42a and the rejection RFID tag 43a are registered (steps S423 and S424). Then, as shown in FIG. 20, the boundary RFID tag 42a is arranged at the boundary of the area A (step S425), and the rejection RFID tag 43a is arranged at the boundary of the allowable area J (step S426). Here, the boundary RFID tag 42a and the rejection RFID tag 43a to be arranged may be single or plural. In the following processing procedure, whether or not the interrogation wave transmission intensity of the antenna 4 varies based on whether or not the confirmation response wave from the boundary RFID tag 42a and the rejection response wave from the rejection RFID tag 43a are received. Determine whether.

  Next, the antenna 4 performs interrogation wave transmission and response wave reception (step S427). Similarly to the processing procedure shown in FIG. 19, it is determined whether or not all the boundary RFID tags 42a arranged at the boundary are read from the received response data (step S428), and all the boundary RFID tags 42a are read. If not (step S428: No), the transmission strength setting unit 7a adjusts the interrogation wave transmission strength (step S429), and sets the adjusted transmission strength as the readable minimum transmission strength. The antenna 4 transmits an interrogation wave again with the readable minimum transmission intensity, and receives a response wave from the RFID tag 2 corresponding to the interrogation wave (step S427). These steps S427 to S429 are repeated until all the boundary RFID tags 42a can be read.

  If all the boundary RFID tags 42a can be read (step S428: Yes), it is determined whether the rejection RFID tag 43a is read (step S430). When the rejection response wave from the rejection RFID tag 43a is received, the interrogation wave has reached the rejection RFID tag 43a arranged at the boundary of the allowable region J. It is considered that the transmission strength has increased compared to the setting. Then, the transmission intensity setting unit 7a adjusts the interrogation wave transmission intensity (step S431), sets the adjusted transmission intensity as the readable minimum transmission intensity, and transmits the interrogation wave again with the readable minimum transmission intensity adjusted by the antenna 4, A response wave corresponding to the interrogation wave is received (step S427). Then, all of the boundary RFID tags 42a can be read (step S428: Yes), and steps S427 to S431 are repeated until the rejection RFID tag 43a is not read (step S430: No).

  If all the boundary RFID tags 42a can be read (step S428: Yes) and the rejection RFID tag 43a cannot be read (step S430: No), the determination unit 7b reads the RFID read together with all the boundary RFID tags 42a. It is determined that the tag 2 is located in the area A (step S432). When the interrogation wave is transmitted with the minimum readable transmission intensity that can read the entire boundary RFID tag 42a and does not read the rejection RFID tag 43a, the interrogation wave of the antenna 4 reaches the boundary of the region A, It does not reach the outside of the allowable area J. For this reason, for example, since the interrogation wave reaches the RFID tag 2a located inside the boundary of the region A, the antenna 4 can receive the response wave from the RFID tag 2a. On the other hand, since the interrogation wave does not reach the RFID tag 2b outside the boundary of the allowable region J, the RFID tag 2b does not receive the interrogation wave transmitted from the antenna 4, and the response wave is transmitted to the antenna according to the interrogation wave. 4 is not sent. For this reason, it is considered that the read RFID tag 2 does not include the RFID tag 2b outside the boundary of the region A.

  Then, the management control unit 8 performs data output for outputting the response data of the RFID tag 2 determined to be located in the area A based on the determination of the determination unit 7b from the management unit 6 to the output unit 11 (step S433). If necessary, the response data is stored in the database 12.

  In this manner, the rejection RFID tag 43a is further arranged at the boundary of the allowable region J, and the interrogation wave of the antenna 4 is readable minimum every time wireless communication is performed based on the reception state of the rejection response wave from the rejection RFID tag 43a. Judgment is made on fluctuations in transmission strength. When the transmission intensity of the interrogation wave of the antenna 4 is increased, the antenna 4 is read until the boundary RFID tag 42a is read and the rejection RFID tag 43a cannot be read so that the arrival position of the interrogation wave becomes the boundary of the region A. The minimum readable intensity of the interrogation wave has been adjusted. Therefore, since the readable minimum transmission intensity of the interrogation wave of the antenna 4 is optimized every time wireless communication is performed, it can be more reliably determined whether or not the read RFID tag 2 is located within the boundary A. . Further, since the rejection RFID tag 43a is arranged, reading of the RFID tag 2 outside the reading area can be surely prevented, and the management target can be managed more accurately. Further, since the boundary RFID tag 42a and the rejection RFID tag 43a are arranged on a predetermined boundary and wireless communication is performed, accurate wireless communication can be performed with a simple device configuration.

  In addition, although the communication system provided with the single antenna 4 was demonstrated as Embodiment 4, not only this but the boundary RFID tag 42 and the rejection RFID tag 43 are arrange | positioned also about the communication system provided with the some antenna. Wireless communication may be performed in the state. Hereinafter, a communication system including a plurality of antennas will be described.

  FIG. 22 is a diagram illustrating the arrangement of RFID tags in a communication system including the x-direction antenna 4a and the y-direction antenna 4b. This communication system has a configuration equivalent to that of the communication system 21 shown in FIG. 5, and after performing the interrogation wave transmission intensity setting process, as shown in FIG. Wireless communication is performed in a state where a plurality of boundary RFID tags 42b to 42e are arranged.

Here, the boundary RFID tag 42b is on the boundary of the region B and is disposed at a position closest to the x-direction antenna 4a. When the response wave for confirmation from the boundary RFID tag 42b cannot be received when the interrogation wave is transmitted with the minimum transmission intensity P _x1 of the x-direction antenna 4a, the transmission intensity of the x-direction antenna 4a varies. it is conceivable that. Therefore, until the boundary RFID tag 42b can be read, the minimum transmission strength P _x1 of the x-direction antenna 4a is adjusted by the same processing procedure as in steps S405 to S407 described above, and the adjusted minimum transmission strength P _x1 is used. A determination process is performed on the read RFID tag. Further, the boundary RFID tag 42c is disposed on the boundary of the region B and at a position farthest from the x-direction antenna 4a. If the response wave for confirmation of the boundary RFID tag 42c cannot be received when the interrogation wave is transmitted with the maximum transmission intensity P _xn of the x-direction antenna 4a, the same processing procedure as that in steps S405 to S407 described above is performed. Then, the maximum transmission intensity P _xn of the x-direction antenna 4a is adjusted, and the determination process is performed on the RFID tag 2 read with the adjusted maximum transmission intensity P _xn . Similarly, for the y-direction antenna 4b, the boundary RFID tag 42d is disposed on the boundary of the region B and closest to the y-direction antenna 4b, and the boundary RFID tag 42e is disposed on the boundary of the region B. 4b is arranged at the farthest position, and adjustment is performed when the transmission intensity varies.

  As described above, even when the x-direction antenna 4a and the y-direction antenna 4b are provided, the interrogation between the x-direction antenna 4a and the y-direction antenna 4b is performed every time wireless communication is performed by similarly arranging the boundary RFID tags 42b to 42e. Since the wave transmission intensity is optimized, it can be more reliably determined whether or not the read RFID tag 2 is located within the boundary B.

Further, as shown in FIG. 23, the RFID tag may be read in a state where an allowable area K is set around the area B and rejection RFID tags 43 b to 43 e are further arranged on the boundary of the allowable area K. After performing the interrogation wave transmission intensity setting process in the same manner as in the second embodiment, each antenna transmits an interrogation wave with the minimum transmission intensity and the maximum transmission intensity. Each time each antenna receives a response wave, it is determined whether or not the boundary RFID tags 42b to 42e can be read in the same procedure as the processing procedure shown in steps S427 to S431 in FIG. It is determined whether 43b to 43e have been read, and the transmission intensity of each antenna is adjusted. If the rejection RFID tag 43b corresponds to the boundary RFID tag 42b and the x-direction antenna 4a transmits the interrogation wave with the minimum transmission intensity _Px1 , the boundary RFID tag 42b is read and the rejection RFID tag 43b is read. No adjustment to transmission strength. The rejection RFID tag 43c corresponds to the boundary RFID tag 42c, the rejection RFID tag 43d corresponds to the boundary RFID tag 42d, and the rejection RFID tag 43e corresponds to the boundary RFID tag 42e.

  As described above, when the x-direction antenna 4a and the y-direction antenna 4b are provided, similarly, the rejection RFID tags 43b to 43e are arranged on the boundary of the allowable area K together with the boundary RFID tags 42b to 42e. Since the transmission intensity of the interrogation wave between the x-direction antenna 4a and the y-direction antenna 4b is made appropriate every time, the determination as to whether or not the read RFID tag 2 is located within the boundary B is performed more reliably. Can do.

  Further, as shown in FIG. 24, a radio communication may be performed in a state where a z-direction antenna 4c that transmits an interrogation wave in the z-direction is further provided and a boundary RFID tag 42a is disposed. 24 illustrates the case where the boundary RFID tag 42a is arranged at the apex of the region Q. However, the present invention is not limited to this, and the boundary RFID tag 42a may be arranged at the boundary of the region Q. And it is good also as a communication system which provides an allowance area | region around the area | region Q, and performs radio | wireless communication in the state which has arrange | positioned the rejection RFID tag 43 in the predetermined position further on the boundary of this allowance area. Even when the z-direction antenna 4c is further arranged, the variation in the transmission intensity is also adjusted for the z-direction antenna 4c by the same processing procedure as that for the x-direction antenna 4a and the y-direction antenna 4b.

  In addition to providing antennas at three locations, when a large number of antennas are provided, similarly, the boundary RFID tag 42 and the reject RFID tag 43 are arranged at predetermined positions to adjust the fluctuations in the transmission intensity of each antenna, and wireless communication May be performed.

  Further, as shown in FIG. 25, the RFID tag 2 may be read in a state where one or a plurality of correction RFID tags 44 are arranged on the boundary of the region B together with the boundary RFID tags 42b to 42e. This communication system has the same configuration as that of the communication system 31 shown in FIG. 13, and after performing the interrogation wave transmission intensity setting process in the same manner as in the third embodiment, the interrogation wave is transmitted and which transmission is performed by the correction RFID tag 44. It is detected whether a response wave is transmitted with respect to the interrogation wave transmitted with intensity. Then, determination processing is performed in the same manner as the processing procedure shown in FIG. 17 using the detected transmission intensity as correction data. In this case, since the corrected RFID tag 44 and the RFID tag 2 that is the target of region determination are read by the same wireless communication, the determination unit 37c determines whether the RFID tag 2 is located in the region B or not. Judgment can be performed in real time. Further, the determination process may be more reliably performed by performing wireless communication in a state where the allowable area K is provided and the rejection RFID tags 43b to 43e are arranged.

  In addition, as shown in FIG. 26, the boundary of the reading area is divided by a partition 47, the boundary RFID tag 42a is disposed at a place where the partition 47 is not disposed, and the rejection RFID tag 43a is disposed outside thereof, Wireless communication may be performed. In this case, the partition 47 has a function of electromagnetically blocking the interrogation wave transmitted by the antenna 4 and the response wave transmitted by the RFID tag 2. For this reason, when adjusting the transmission intensity fluctuation of the antenna 4, it is sufficient to arrange the boundary RFID tag 42 a in a place not partitioned by the partition 47. In addition, it is sufficient to arrange the rejection RFID tag 43a outside the place not partitioned by the partition 47. This is because the interrogation wave does not reach the outside from the partition 47 if it is a place partitioned by the partition 47. In this way, by dividing the boundary of the reading area using the partition 47, even when a large number of boundary RFID tags 42a and rejection RFID tags 43a are not arranged at or around the boundary of the reading area, they are positioned in the reading area. The response data of the RFID tag 2 can be output accurately. Note that the boundary RFID tag 42a and the rejection RFID tag 43a may be arranged singly rather than plural.

  The processing units 7, 27, and 37 and the management control unit 8 have programs that define various processing procedures and the like, operate these programs, and perform transmission intensity setting processing, determination processing, and correction according to the above-described procedures. Data detection processing is performed, and output processing of information transmitted from the information medium is performed.

  In the first to fourth embodiments, the RFID tag 2 that obtains an operating power from radio waves received from the antennas 4, 4a, and 4b has been described. However, the present invention is not limited thereto, and a battery function such as a battery serving as a power source is provided inside. Wireless communication may be performed with the RFID tag. In the first to fourth embodiments, the antenna control unit 5 is common to the antennas 4a and 4b. However, the present invention is not limited to this, and the antenna control unit 5 may be provided for each antenna.

  In the first to fourth embodiments, the single region A or the region B has been described. However, the present invention is not limited to this, and the RFID tag 2 that transmits a response wave for each reading region is not limited to this. It may be determined whether or not it is located within the region. In this case, a plurality of transmission intensities of the antennas 4, 4 a, 4 b are set, and the RFID tag 2 that has transmitted the response wave selects, extracts or excludes the RFID tag 2 according to the corresponding transmission intensity, and performs region determination. Also good. Moreover, you may provide the antenna 4,4a, 4b for each area | region.

  In the first to fourth embodiments, the communication system having a reading function for reading the identification information of the RFID tag 2 has been described. However, the communication system may further include a writing function for rewriting information stored in the RFID tag 2. . When information is rewritten only to the RFID tag 2 located in the predetermined area, the above-described processing procedure is performed to discriminate the RFID tag 2 located in the predetermined area, thereby obtaining accurate information. Rewriting is possible.

  Moreover, in Embodiments 1 to 4, the setting RFID tag is used to adjust the transmission intensity at which the setting RFID tag can be read and the readable minimum transmission intensity is set. Along with the adjustment, the antennas 4, 4a, 4b may be moved to adjust the reach distance of the interrogation wave. Thus, even when the transmission intensity is set by moving the antennas 4, 4 a, 4 b, the fact that the interrogation wave reaches different distances varies depending on the transmission intensity, and is located in the reading area by the above-described processing procedure. The RFID tag 2 can be determined.

  In the first to fourth embodiments, the RFID tag 2 has been described as an example of an information medium. However, the present invention is not limited thereto, and any information medium including an antenna and a memory that stores identification information or the like may be used. In this case, any communication system including the antennas 4, 4a, 4b and the antenna control unit 5 corresponding to this information medium may be used, and response data transmitted from the information medium located in the reading area in accordance with the processing procedure described above. Can be output.

1 is a block diagram showing a schematic configuration of a communication system according to a first exemplary embodiment. It is a flowchart which shows the process sequence until the response data of a RFID tag is output. It is a flowchart which shows the process sequence until it achieves a query wave transmission intensity | strength setting process. It is a figure explaining an interrogation wave transmission intensity setting process concretely. It is a figure explaining an interrogation wave transmission intensity setting process concretely. FIG. 3 is a block diagram showing a schematic configuration of a communication system according to a second exemplary embodiment. It is a flowchart which shows the process sequence until the response data of a RFID tag is output. It is a flowchart which shows the process sequence until it achieves a query wave transmission intensity | strength setting process. It is a figure explaining an interrogation wave transmission intensity setting process concretely. It is a flowchart which shows the process sequence until it achieves a determination process. It is a figure explaining a determination process concretely. It is a figure explaining a determination process concretely. It is a figure explaining arrangement | positioning of the antenna of the communication system concerning Embodiment 2. FIG. FIG. 12 is a diagram specifically explaining a determination process of the communication system shown in FIG. 11. FIG. 12 is a diagram specifically explaining a determination process of the communication system shown in FIG. 11. FIG. 6 is a block diagram showing a schematic configuration of a communication system according to a third exemplary embodiment. It is a flowchart which shows the process sequence until the response data of a RFID tag is output. It is a flowchart which shows the process sequence until it achieves a correction data detection process. It is a figure explaining correction data detection processing concretely. It is a figure explaining correction data detection processing concretely. It is a figure explaining correction data detection processing concretely. It is a flowchart which shows the process sequence until it achieves a determination process. It is a figure explaining arrangement | positioning of the RFID tag of the communication system concerning Embodiment 4. FIG. It is a flowchart which shows the process sequence until the response data of a RFID tag is output. It is a figure explaining the other example of arrangement | positioning of the RFID tag of the communication system concerning Embodiment 4. FIG. It is a flowchart which shows the process sequence until the response data of a RFID tag is output. It is a figure explaining the other example of arrangement | positioning of the RFID tag of the communication system concerning Embodiment 4. FIG. It is a figure explaining the other example of arrangement | positioning of the RFID tag of the communication system concerning Embodiment 4. FIG. It is a figure explaining the other example of arrangement | positioning of the RFID tag of the communication system concerning Embodiment 4. FIG. It is a figure explaining the other example of arrangement | positioning of the RFID tag of the communication system concerning Embodiment 4. FIG. It is a figure explaining the other example of arrangement | positioning of the RFID tag of the communication system concerning Embodiment 4. FIG.

Explanation of symbols

1,21,31 Communication system 2, 2a, 2b RFID tag 2s Setting RFID tag 4 Antenna 4a X direction antenna 4b Y direction antenna 4c Z direction antenna 5 Antenna control unit 5a Control unit 5b Transmission / reception unit 6 Management unit 7, 27, 37 processing unit 7a, 27a, 27a transmission intensity setting unit 7b, 27b, 37c determination unit 8 management control unit 9 memory 10 operation unit 11 output unit 12 database 37b correction data detection unit 42a, 42b, 42c, 42d, 42e Boundary RFID tag 43a, 43b, 43c, 43d, 43e Rejection RFID tag 44 Correction tag

Claims (11)

An information medium for transmitting a response wave including identification information according to the received interrogation wave, and an antenna for transmitting the interrogation wave to the information medium and receiving the response wave from the information medium according to the interrogation wave In a communication system for performing wireless communication with the reading means,
A communication system comprising: determination means for determining the information medium located in a preset reading area based on a reception state of the response wave with respect to the transmission intensity of the interrogation wave. Transmission intensity setting means for setting a readable minimum transmission intensity that is a minimum intensity of the transmission intensity of the interrogation wave that reaches the boundary of the reading area;
The determination means determines the information medium located in the reading area based on a reception state at the antenna of the response wave transmitted by the information medium according to the interrogation wave having the readable minimum transmission intensity. The communication system according to claim 1.   The determination means determines the information medium that has transmitted the response wave received by the antenna as the information medium located in the reading area, in accordance with the interrogation wave having the readable minimum transmission intensity. The communication system according to claim 1, wherein the communication system is characterized.   The communication system according to claim 1, further comprising a plurality of the antennas that transmit the interrogation waves from different directions with respect to the reading area. The transmission strength setting means sets the first readable minimum transmission strength and the second readable minimum transmission strength that is different from the first readable minimum transmission strength.
The determination means selects the information medium that has transmitted the response wave received by the antenna for each readable minimum transmission intensity of the interrogation wave that the information medium responds to, and the first readable minimum transmission intensity. The information medium corresponding to the second readable minimum transmission intensity is excluded from the determination target, and the remaining information medium is located in the reading area. The communication system according to claim 1, wherein the communication system is determined as an information medium. The first readable minimum transmission intensity is the minimum intensity of the transmission intensity at which the interrogation wave reaches a position farthest from the antenna at the boundary of the reading area,
The second readable minimum transmission intensity is the minimum intensity of the transmission intensity at which the interrogation wave reaches the boundary of the reading area and closest to the antenna;
For a boundary that is different from the first readable minimum transmission intensity and the second readable minimum transmission intensity and is the minimum intensity of the interrogation wave reaching any position on the boundary of the reading area A correction data detecting means for detecting the minimum transmission intensity as correction data;
6. The antenna transmits the interrogation wave with the first readable minimum transmission intensity, the second readable minimum transmission intensity, and the boundary minimum transmission intensity corresponding to the correction data. The communication system according to 1.   The determination means compares the correction data with the transmission intensity of the interrogation wave corresponding to the information medium that has transmitted the response wave, and determines the information medium that is located in the reading area. The communication system according to claim 6. It further includes a boundary confirmation information medium that is arranged at an arbitrary position on the boundary of the reading region and transmits a confirmation response wave according to the interrogated wave that has reached.
8. The transmission intensity setting means adjusts the readable minimum transmission intensity based on a reception state of the confirmation response wave with respect to the interrogation wave transmitted with the readable minimum transmission intensity. The communication system according to any one of the above. A rejection information medium that is disposed at a boundary of an allowable area provided around the reading area and that transmits a rejection response wave in response to the interrogated wave that has arrived;
The transmission intensity setting means adjusts the readable minimum transmission intensity based on a reception state of the rejection response wave with respect to the interrogation wave transmitted with the readable minimum transmission intensity. The communication system according to any one of the above.   The said transmission strength setting means reduces the said readable minimum transmission strength when the said response wave for rejection with respect to the said interrogation wave transmitted with the said readable minimum transmission strength is received. Communications system. The communication according to any one of claims 1 to 10, further comprising a blocking unit that electromagnetically blocks the interrogation wave and / or the response wave at least at a part of a boundary of the reading area. system.

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