JP2007013897A - Wireless tag communication apparatus and wireless tag communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless tag communication apparatus in which a wireless tag can be efficiently read while reducing a processing time by reducing the collision frequency of a response wave of the wireless tag when performing multi-read/write processing upon a plurality of wireless tags, in the case variations of a tag detection result are reduced in comparison with the reading frequency of the wireless tag communication apparatus. <P>SOLUTION: The wireless tag communication apparatus 110 comprises a read means for creating optimized reading order information from the last reading result of wireless tag read processing and performing wireless tag reading processing in accordance with the reading order information. The read means creates optimized reading order information(specifically, e.g., a read history excluding read histories determined as "collision" in the reading result) again from the current result (read history) of wireless tag read processing, and performs the next wireless tag read processing based on the reading order information created from the current result of wireless tag read processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless tag communication apparatus and a wireless tag communication method for performing wireless communication with a plurality of wireless tags existing in a communicable region.

  2. Description of the Related Art In recent years, wireless tag communication devices that perform wireless information communication with wireless tags are used in systems such as logistics management, entrance / exit management, and personal authentication. For example, in physical distribution management, a wireless tag recording destination and delivery history information is attached to an article on a belt conveyor, and wirelessly communicated with a wireless tag communication device fixed near the belt conveyor. Wireless tags are used for systems such as automatic sorting of delivery destinations of articles and systems for managing delivery histories.

  The RFID tag communication apparatus as described above is usually configured to perform multi-read / write when a plurality of RFID tags simultaneously enter the communicable area of the RFID tag communication apparatus in order to read information from other RFID tags. Processing is in progress.

  One method of performing multi-read / write processing is to use time slots. In this method, first, the wireless tag communication device transmits a command for confirming the ID (identification code) of the wireless tag. Next, the wireless tag that has received the ID confirmation command from the wireless tag communication device creates a time slot that determines the timing for returning the ID by the individual ID and the random number generator. Returns the ID. In this way, the wireless tag communication device can acquire the IDs of a plurality of wireless tags.

  However, if the response timing at which a random number is generated by a time slot matches a plurality of wireless tags, the wireless tag communication device cannot acquire an ID. In this case, the RFID tag communication apparatus first designates the ID of the RFID tag that can be read, and instructs the command not to return a response wave. Next, an ID confirmation command is transmitted again to the wireless tag that could not be read. The wireless tag that has received the command creates a time slot again, and returns an ID when the time of the time slot is reached. In this way, the wireless tag communication device acquires the ID of the wireless tag that could not be acquired.

  The IDs of a plurality of wireless tags can be acquired by multi-read / write processing. However, if the number of times wireless tag response waves collide increases, the number of ID confirmation command transmissions also increases. There arises a new problem that the ID reading processing time is increased. For this reason, it is necessary to prevent collision of response waves of a plurality of tags and to shorten the processing time for reading the ID of the wireless tag.

  As a conventional technique for preventing collision of response waves of a plurality of tags in multi-read / write processing and shortening processing time, for example, there is a wireless tag system disclosed in Patent Document 1 below. In this conventional technique, in the multi-read / write processing of the wireless tag system, the wireless tag communication device sets the wireless tag time slot to be larger than the number of wireless tags, thereby preventing collision of response waves of the wireless tag. In addition, the response to the wireless tag communication device is continuously returned from the wireless tag in the order of the time slot, but when no response is returned for a certain time, it is determined that there is no tag data of the wireless tag in the time slot, A command for reading the next time slot number is transmitted to the wireless tag.

  By using this conventional technology, it is possible to shorten the reading process time of the ID of the wireless tag. However, in the method using the time slot, it is necessary to hold a random number generator for the wireless tag to create the time slot and a timer for counting the time of the time slot, and the wireless tag requires a complicated configuration. Is done. Therefore, this prior art is not suitable for a wireless tag with a simple configuration such as a batteryless and passive wireless tag.

  Recently, a wireless tag to be attached to anything is a wireless tag with a simple configuration that does not cost much. There is a need for a method for efficiently performing multi-read / write processing on such a wireless tag and reducing the time required for the wireless tag reading processing.

  As another method of performing the multi-read / write processing, there is a binary tree method. Since this method does not require a complicated configuration for the wireless tag, it is suitable for a method for reading a passive wireless tag.

  When reading a wireless tag by the binary tree method, the wireless tag communication device transmits a read command by specifying a mask value for the tag ID, and the wireless tag receiving the command has its own ID and the read command mask value. And return the response wave.

The reading process of the wireless tag by the binary tree method will be described with reference to FIG.
FIG. 21 illustrates an operation when the wireless tag communication apparatus reads three types of tags having IDs of 001, 011 and 110.

  First, the RFID tag communication apparatus performs reading without setting a mask value. Then, since the three types of tags return responses, collision is detected. By this collision, it can be seen that the RFID tag communication apparatus has a plurality of tags. Therefore, reading is performed by specifying a mask value of “0” so that only a tag whose first bit is 0 returns a response wave. Then, since the wireless tags with IDs 001 and 011 return response waves, collision is detected. By this collision, it can be seen that there are a plurality of tags whose first bit is 0 in the wireless tag communication apparatus. Next, reading is performed by specifying a mask value of “00” so that only a tag whose first bit is “0” and second bit is “0” returns a response wave. Then, since only the wireless tag with ID 001 returns a response wave, the wireless tag communication apparatus can recognize that the wireless tag with ID 001 exists. According to a similar procedure, the other two IDs (011, 110) are also recognized.

In the wireless tag reading process using the binary tree method, the number of communication increases as the number of tag ID collisions increases. Also, in the RFID tag reading process using the binary tree method, reading is always started without specifying a mask value, and when a collision is detected, a mask value is set whenever necessary, and the RFID tag ID is acquired by reading. To go.
JP 2000-113127 A

  However, in the case where fluctuations in the tag detection result are small compared to the frequency of reading by the RFID tag communication device, for example, an area where the RFID tag is attached can be communicated with the RFID tag communication device installed on the article shelf. In the article management system that constantly monitors the return / removal of articles by reading the wireless tag existing in the system, it always starts from reading without specifying a mask value, like the reading process of the wireless tag by the binary tree method, When a collision is detected, it is inefficient to perform a reading process using a method of setting a mask value at any time and performing reading.

  Therefore, the present invention compares the reading frequency of the RFID tag communication device, and in the case where the fluctuation of the tag detection result is small, the RFID tag when performing the multi-read / write processing on a plurality of RFID tags. It is an object of the present invention to provide a wireless tag communication device capable of efficiently reading a wireless tag, which can reduce the number of response wave collisions and shorten the processing time.

  In order to achieve the above object, in the RFID tag communication apparatus according to the present invention, RFID tag communication for performing predetermined information processing by performing RFID tag reading processing representing transmission / reception of information wirelessly with the RFID tag. An apparatus comprising: a reading unit that generates optimized reading order information from a previous reading result of the RFID tag reading process, and performs RFID tag reading processing according to the reading order information; The optimized reading order information is created again from the current reading result of the process, and the next RFID tag reading process is performed based on the reading order information created from the result of the RFID tag reading process this time. .

  More specifically, the reading unit stores in the reading history storage unit reading history information that is a set of a mask value specified at the time of reading processing of the wireless tag communication device and a reading result when the mask value is specified. The reading history information excluding the reading history information whose reading result is “collision” is stored in the reading order storage unit as reading order information, and the reading order information is stored in the next reading process. It is characterized by performing reading based on the above. Further, after performing the reading process according to the reading order information, the number of communication can be reduced by updating the stored reading order information according to the response result inferred from the reading history information according to the rules of the binary tree method. And

  Note that the present invention can be realized not only as such a wireless tag communication apparatus, but also as a wireless communication tag method including steps characteristic of the wireless tag communication apparatus. It can also be realized as a program for causing a computer to execute steps. Needless to say, such a program can be distributed via a recording medium such as a CD-ROM or a transmission medium such as the Internet.

  As is apparent from the above description, according to the present invention, when the fluctuation of the tag detection result is small compared with the reading frequency of the RFID tag communication apparatus, the reading process is performed based on the previous reading result. By doing so, the wireless tag can be read efficiently, and the time required for the reading process can be shortened.

  Therefore, according to the present invention, it is possible to shorten the time required for reading information from the wireless tag as compared with the conventional method, and the practical value of the present invention in the present day when the system using the passive wireless tag is widespread is extremely high. high.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an overall configuration of a system using an RFID tag communication apparatus according to the present invention.

  As shown in FIG. 1, this system includes a PC 100, a wireless tag communication device 110, and a plurality of wireless tags (hereinafter also simply referred to as “tags”). In FIG. 1, the arrangement of the wireless tags (120 to 123) in the communicable area 130 of the wireless tag communication device 110 connected to the PC 100 is shown.

  The wireless tag communication device 110 can communicate with wireless tags (four wireless tags 120 to 123 in the illustrated example) existing in the communicable area 130.

FIG. 2 is a block diagram showing a detailed configuration of the RFID tag communication apparatus 110 shown in FIG.
As shown in FIG. 2, the wireless tag communication device 110 includes a communication antenna 200 for communicating with a wireless tag, a transmission / reception unit 201, a tag information storage unit 202, a mask value storage unit 203, and a reading history storage. Unit 204, reading order storage unit 205, mask value creation unit 206, reading result determination unit 207, PC command processing unit 208, and PC communication control unit 209.

The transmission / reception unit 201 controls transmission / reception with the wireless tag via the communication antenna 200.
The tag information storage unit 202 stores the ID of the wireless tag received by the communication antenna 200.

  The mask value storage unit 203 stores a wireless tag ID (mask value) specified by the wireless tag communication device 110 when reading the wireless tag in order to prevent collision of response waves from the wireless tag.

  The reading history storage unit 204 stores reading history information in which a mask value specified when the RFID tag communication apparatus 110 performs reading and a reading result when reading is performed by specifying the mask value.

  The reading order storage unit 205 stores reading order information of a read command that the wireless tag communication device 110 transmits to the wireless tag.

The mask value creation unit 206 creates a mask value.
A reading result determination unit 207 determines a reading result by the wireless tag communication device.

The PC command processing unit 208 analyzes a command received from the PC.
The PC communication control unit 209 controls communication with the PC.

  FIG. 3 is a block diagram showing a detailed configuration of the wireless tag shown in FIG. Since the wireless tags 120 to 123 have the same configuration, the representative thereof will be described as the wireless tag 300.

  As illustrated in FIG. 3, the wireless tag 300 includes an antenna unit 301 for performing communication with the wireless tag communication device, a transmission / reception unit 302, a storage unit 303, and a control unit 304.

The transmission / reception unit 302 controls communication with the wireless tag communication device via the antenna unit 301.
The storage unit 303 stores an ID (identification code) unique to the wireless tag.

FIG. 4 is a diagram showing a wireless tag ID list 400 in the state of FIG.
It is a figure which shows the specific example of ID (tag ID) 400 memorize | stored in the memory | storage part 303 of a wireless tag (120-123). The storage unit 303 stores 0000 for the tag 120, 0010 for the tag 121, 1110 for the tag 122, and 1111 for the tag 123.

  The control unit 304 determines transmission of the ID stored in the storage unit 303 based on the mask value received from the wireless tag communication device.

  The operation of the RFID tag communication apparatus 110 configured as described above will be described below.

  FIG. 5 is a flowchart showing a wireless tag reading process by the binary tree method of the wireless tag communication apparatus 110 according to the present embodiment.

  When the PC communication control unit 209 receives a read command from the PC 100 and the PC command processing unit 208 determines that it is a read command, the wireless tag reading process is started (step 501). First, a mask value is created by the mask value creation unit 206 (step 502). In the first reading process, the mask value is created with “” (none). Next, the transmission / reception unit 201 transmits a read command including the created mask value from the communication antenna 200 (step 503). Thereafter, when the transmission / reception unit 201 receives a response from the wireless tag by the communication antenna 200 or waits for a response from the wireless tag for a predetermined time and determines that there is no response from the wireless tag, the reading history storage unit 204 stores the response. The reading history information in which the mask value designated in the current reading process and the reading result are paired is stored (step 504). Next, the reading result determination unit 207 determines whether or not the reading result is “collision” (step 505).

  If the read result is “collision”, a new mask value is created (step 506), and the newly created mask value is stored in the mask value storage unit 203 (step 507). Then, the presence / absence of data in the mask value storage unit 203 is confirmed (step 508), and if there is other mask value data in the mask value storage unit 203, the mask value storage unit 203 selects any data based on a predetermined method. Is acquired, and the acquired mask value data is set in the read command as the next mask value (step 509), and the reading process is started again. In the confirmation of the presence or absence of data in the mask value storage unit 203 (step 508), if there is no data in the mask value storage unit 203, the reading process is terminated (step 512).

  When the reading result determination unit 207 determines that the reading result is not “collision”, the reading result determination unit 207 determines whether or not there is a response (step 510). If there is a response, the tag ID as a read result is stored in the tag information storage unit 202 (step 511), and then the process proceeds to a process for checking whether there is data in the mask value storage unit 203 (step 508). If there is no response, the process proceeds to the confirmation process of the presence / absence of data in the mask value storage unit 203 (step 508).

  Here, in the determination of whether or not the reading result in step 505 is “collision”, the mask value creation (step 506) to mask value storage (step 509) processing, which is processing when the reading result is “collision”. Will be described with reference to FIG.

  In creating a mask value, first, the current mask value is acquired (step 602), and a mask value with “1” added to the end of the current mask value is created (step 603). Next, the mask value created in step 603 is stored in the mask value storage unit 203 (step 604). Next, a mask value with “0” added to the end of the current mask value is created (step 605), and the created mask value is stored in the mask value storage unit 203 (step 606). In the present embodiment, a new mask value is created by adding numbers in the order of “1” and then “0” at the end of the current mask value in step 605 using FIG. However, the order may be reversed.

The mask value storage unit 203 stores and retrieves mask values using LIFO.
FIG. 7 is a diagram showing processing by LIFO in the mask value storage unit 203.

  FIG. 7 shows that mask values “1” and “0” are sequentially recorded in the mask value storage unit 203 and the last stored mask value “0” is taken out.

  In the present embodiment, first, when the mask value is set to “none” (step 502) and the reading process is performed (step 503), all the wireless tags in the communicable area 130 of the wireless tag communication device 110 are used. (120 to 123) returns a response. When a response from the wireless tag is received, reading history information of a set of “mask value: none, reading result: collision” is stored in the reading history storage unit 204 (step 504). Next, it is confirmed whether or not the read result is “collision” (step 505). Since the read result is “collision”, “1” and “0” are sequentially stored in the mask value storage unit 203 (steps 506 and 507). Next, the presence or absence of data in the mask value storage unit is confirmed (step 508). Since “1” and “0” are stored in the mask value storage unit, it is determined that “data is present”. Then, according to the LIFO process, the mask value “0” is acquired from the mask value storage unit and set as a new mask value (step 509). The mask value is set to “0” and the reading process is started again (step 503). The reading process is repeated until there is no data in the mask value storage unit.

  In the reading process of the wireless tag, if the reading result is “collision”, the mask value with “1” added and the mask value with “0” added are specified after the current mask value sequence and read again. Process. Therefore, the reading process of the wireless tag can be represented by a binary tree in which branches are represented by mask values.

FIG. 8 is a diagram showing the reading process in the present embodiment as a binary tree.
FIG. 9 shows reading history information stored in the reading history storage unit 204 when the RFID tag reading process is performed based on the RFID tag reading process flowchart of FIG. 5 in the present embodiment.

  When the reading process of the wireless tag is completed, the next reading order of the wireless tag is determined based on the reading history information stored in the reading history storage unit 204.

FIG. 10 shows a flowchart of processing for determining the reading order of the wireless tags.
This process is repeated for the number of pieces of reading history information stored in the reading history storage unit 204 (step 1002 to step 1006). First, one piece of reading history information is acquired from the reading history storage unit 204 (step 1003), and it is determined whether or not the reading result is “collision” (step 1004). When the reading result is “collision”, one piece of next data is acquired from the reading history storage unit 204 (step 1003), and the same processing is performed. When the reading result is not “collision”, the reading history information acquired from the reading history storage unit 204 is stored as reading order information in the reading order storage unit (step 1005). Then, one piece of next reading history information is acquired from the reading history storage unit 204 (step 1003), and the same processing is performed. When the reading order information stored in the reading history storage unit 204 shown in FIG. 9 is subjected to the reading order determination process shown in FIG. 10, the reading order storage unit 205 stores the reading order information shown in FIG.

  The wireless tag communication device 110 performs the next wireless tag reading process with reference to the reading order information in the reading order storage unit 205. If there is no change in the reading result in the next wireless tag reading process, that is, if the wireless tags existing in the communicable area of the wireless tag communication apparatus are the same, the wireless tag can be read with the minimum necessary reading process. . For this reason, in a system in which the wireless tag read by the wireless tag communication device is known in advance and the wireless tag communication device always reads the wireless tag, the wireless tag can be read efficiently.

  Next, a case where there is a change in the reading result in the next wireless tag reading process will be described. First, a case where another wireless tag is newly read in addition to the tag read in the first reading process will be described. In this case, FIG. 12 shows a tag ID list 1200 read by the wireless tag reading process. The wireless tags newly read in the next reading process are the wireless tag 1201 (ID: 0011) and the wireless tag 1202 (ID: 1000).

  The next reading process is performed based on the reading order information (FIG. 11) in the reading order storage unit 205. In the next reading process, another wireless tag (1201, 1202) is newly detected in the communicable area 130 of the wireless tag communication device 110. Here, FIG. 13 shows a flowchart of the reading order update process when another wireless tag is newly detected in the communicable area 130 of the wireless tag communication device 110.

  First, the RFID tag communication apparatus 110 acquires reading order information from the reading order storage unit 205 (step 1303). Next, reading processing is performed based on the mask value of the acquired reading order information (step 1304). After that, when the transmission / reception unit 201 receives a response from the wireless tag with the communication antenna 200 or waits for a certain time from the wireless tag for a response and determines that there is no response from the wireless tag, the read result is “collision”. Whether or not (step 1305). If the reading result is a collision, a mask value is created by adding “1” added to the end of the mask value used in the current reading process (step 1306), and the created mask value is used as the next reading order information. Is additionally stored in the reading order storage unit 205 (step 1307). Next, a mask value with “0” added to the end of the current mask value is created (step 1308), and the created mask value is additionally stored in the reading order storage unit 205 as the next reading order information (step 1309). . Then, reading history information obtained by combining the current mask value and the reading result is stored in the reading history storage unit 204 (step 1310). The presence or absence of the next data in the reading order storage unit 205 is checked (step 1302). If the result of the reading process is not “collision”, reading history information obtained by combining the current mask value and the reading result is stored in the reading history storage unit 204 (step 1310). The presence or absence of the next data in the reading order storage unit 205 is checked (step 1302).

  In actual operation, first, the first reading order information (mask value: 000, reading result: 0000) is obtained from the reading order storage unit 205 (step 1303). The wireless tag is read by designating the mask value (000) of the reading order information (step 1304). Then, it is checked whether or not the read result is “collision” (step 1305). Since the reading result is “tag ID (0000)” and not “collision”, the set of the current mask value (000) and the current reading result (0000) is stored in the reading history storage unit 204 as reading history information. (Step 1310). Next, the next reading order information (mask value: 001, reading result: 0010) is acquired from the reading order storage unit 205 (step 1303). The mask value of the acquired reading order information is designated as “001” and reading processing is performed (step 1304). Then, it is checked whether or not the read result is “collision” (step 1305). In this case, since the reading result is “collision”, the reading order storage unit uses the mask value with “0” added to the end of the mask value “001” and the mask value with “1” added as the next reading order information. 205 is additionally stored. (Steps 1306 to 1309). Then, a set of the current mask value (001) and the current reading result (collision) is stored in the reading history storage unit 204 as reading history information (step 1310). Next, the next reading order information (mask value: 0010, reading result: none) is acquired from the reading order storage unit 205, and similarly, the mask value is designated and reading processing is performed. Thereafter, the same processing is repeated until there is no reading order information. FIG. 14 shows the reading history information stored in the reading history storage unit 204 when the reading order information disappears and the processing is completed. Further, FIG. 15 shows a diagram representing the reading process in the present embodiment by a binary tree. By processing the reading history information in the reading history storage unit 204 shown in FIG. 14 based on the reading order creation processing flowchart shown in FIG. 10, the next reading order information is stored in the reading order storage unit 205. The next reading order information is shown in FIG. The reading process from the next time is performed with reference to the updated reading order information.

  Next, a case where only some of the wireless tags read in the first reading process can be read will be described. In this case, FIG. 17 shows a tag ID list 1700 read by the wireless tag reading process. The wireless tags that can be read by the next reading process are the wireless tag 120 (ID: 0000) and the wireless tag 123 (ID: 1111).

  The next reading process is performed based on reading order information (FIG. 11) in the reading order storage unit 205. FIG. 18 shows reading history information 1800 when reading processing is performed with reference to reading order information (FIG. 11) stored in the reading order storage unit 205. In the previous reading history information, when the wireless tag was read by specifying “001” and “1110” as mask values, the tag ID was detected. However, in this reading process, “no response” is detected. Become.

  In the reading history information 1800 stored in the reading history storage unit 204, the ID of the wireless tag was detected in the previous reading process, but based on the information indicating “no response” in the current reading process, the next time FIG. 19 shows a flowchart of the reading order determination process for determining the reading order.

  First, reading history information A is acquired from the reading history storage unit 204 (step 1903). Next, it is confirmed whether or not the reading history information for the mask value that differs only in the last mask value of the acquired reading history information exists in the reading history storage unit 204 (step 1904). If there is no reading history information, the next reading history information in the reading history storage unit 204 is acquired (step 1903), and the processing of step 1904 is performed again.

  If there is reading history information, reading history information B is acquired from the reading history storage unit 204 (step 1905). When the reading results of the reading history information A and B are both tag IDs, the next reading history is acquired from the reading history storage unit 204 (step 1903), and the processing of step 1904 is performed again.

  If the reading result of the reading history information A is the tag ID and the reading result of the reading history information B is “no response”, the reading history information A is updated (step 1908). In updating the reading history A, the mask value is updated to a value obtained by deleting the last value of the current mask value. The read result is unchanged. Next, the reading history information B is deleted from the reading history storage unit (step 1909), the updated reading history information A is newly set as the reading history information A (step 1912), and the processing from step 1904 is performed again.

  If the reading result of the reading history information A is “no response”, the reading history information B is updated (step 1910). In updating the reading history information B, the mask value is updated to a value obtained by deleting the last value of the current mask value. The read result is unchanged. Next, the reading history information A is deleted from the reading history storage unit 204 (step 1911), the updated reading history information B is newly set as the reading history information A (step 1912), and the processing from step 1904 is performed again. .

  In actual operation, first, the first reading history information A (mask value: 000, reading result: 0000) is acquired. The mask value that differs only in the last value of the mask value “000” is “001”, and reading history information B (mask value: 001, reading result: no response) of this mask value is acquired from the reading history storage unit 204. Since the reading result of the reading history information A is the tag ID and the reading result of the reading history information B is “no response”, the reading history information A is updated (mask value: 00, reading result: 0000). The Then, the reading history information B is deleted from the reading history storage unit. With this processing, in the next reading processing, if there is no change in the wireless tag existing in the communicable area of the wireless tag communication device, the reading result “0000” is obtained when the reading processing is performed by designating the mask value “00”. Is obtained. Also, by specifying the mask value “00”, the ID of the tag of the read result “0000” can be acquired when the read process is performed, so the read process with the mask value “001” becomes unnecessary.

  Next, the updated reading history information A (mask value: 00, reading result: 0000) is set again as the reading history information A. The mask value that differs only at the end of the mask value “00” is “01”, and the reading history B (mask value: 01, reading result: no response) of this mask value is acquired. Since the reading result of the reading history information A is the tag ID and the reading result of the reading history information B is “no response”, the reading history information A is updated (mask value: 0, reading result: 0000). The Also, the reading history B is deleted from the reading history storage unit. With this processing, in the next reading processing, if there is no change in the wireless tag existing in the communicable area of the wireless tag communication device, the reading result “0000” is obtained when the reading processing is performed by designating the mask value “0”. Is obtained. In addition, by specifying the mask value “0”, the ID of the tag of the reading result “0000” can be acquired when the reading process is performed, so that the reading process with the mask value “01” becomes unnecessary.

  Next, the updated reading history A (mask value: 0, reading result: 0000) is set again as the reading history A. The mask value that differs only at the end of the mask value “0” is “1”. There is no reading history information of this mask value. This means that there are a plurality of wireless tags whose first bit is “1”, and reading processing is performed by specifying a mask value longer than the mask value “1”.

  Next, the next reading history (mask value: “1110”, reading result: no response) A in the reading history storage unit is acquired.

  Thereafter, when processing is performed according to a similar procedure, the reading history information 2000 shown in FIG. 20 is updated. The reading history information 2000 is created in accordance with the flowchart shown in FIG. 10 to generate reading order information, and the next reading process is performed.

  Note that the update of the reading history storage unit based on the flowchart of FIG. 19 can also be performed during the reading process.

  The wireless tag communication device of the present invention is used for systems such as physical distribution management, entrance / exit management, and personal authentication, and is suitable for a device that wirelessly communicates information with a wireless tag. Specifically, for example, an article with a wireless tag attached is constantly monitored for return / removal of the article by reading a wireless tag existing in a communicable area with a wireless tag communication device installed on the article shelf. This is suitable for the article management system.

It is a figure which shows the whole structure of the system in embodiment of this invention. It is a block diagram which shows the detailed structure of the radio | wireless tag communication apparatus shown by FIG. It is a block diagram which shows the detailed structure of the radio | wireless tag shown by FIG. It is a figure which shows ID list of a wireless tag. It is a flowchart which shows the radio | wireless tag reading process by the binary tree system of a radio | wireless tag communication apparatus. It is a flowchart which shows the mask value creation process in the radio | wireless tag reading process by the binary tree system of a radio | wireless tag communication apparatus. It is a figure which shows the LIFO process of the mask value in the reading process of the wireless tag by the binary tree system of a wireless tag communication apparatus. It is a binary tree for demonstrating the reading process of the wireless tag by the binary tree system of a wireless tag communication apparatus. It is a figure which shows the reading history information memorize | stored in the reading history memory | storage part by the wireless tag reading process of a wireless tag communication apparatus. It is a flowchart which shows the process which produces reading order information from the reading history information of the wireless tag reading process of a wireless tag communication apparatus. It is a figure which shows the reading order information produced from the reading history information of the wireless tag reading process of a wireless tag communication apparatus. It is a figure which shows the ID list of the radio | wireless tag which a radio | wireless tag communication apparatus reads when two types of tags newly enter in the communication area | region of a radio | wireless tag communication apparatus. It is a flowchart which shows the reading order information update process performed at the time of the radio | wireless tag reading process of the radio | wireless tag communication apparatus when two types of tags newly enter in the communication area | region of a radio | wireless tag communication apparatus. It is a figure which shows the reading log | history information memorize | stored in the reading log | history memory | storage part by the radio | wireless tag reading process of a radio | wireless tag communication apparatus, when two types of tags newly enter in the communication area | region of a radio | wireless tag communication apparatus. It is a binary tree for demonstrating the reading process of the radio | wireless tag by the binary tree system of the radio | wireless tag communication apparatus when two types of tags newly enter in the communication area | region of the radio | wireless tag communication apparatus. It is a figure which shows reading order information when the reading order information update process performed at the time of the radio | wireless tag communication process of a radio | wireless tag communication apparatus when two types of new tags enter in the communication area | region of a radio | wireless tag communication apparatus is complete | finished. It is a figure which shows the ID list of the wireless tag which a wireless tag communication apparatus reads, when two types of tags remove | deviate from the inside of the communication area | region of a wireless tag communication apparatus. It is a figure which shows the reading log | history information memorize | stored in the reading log | history memory | storage part by the radio | wireless tag reading process of a radio | wireless tag communication apparatus when two types of tags remove | deviate from the inside of the communication area | region of a radio | wireless tag communication apparatus. The flowchart which shows the reading history information update process which updates the reading history information memorize | stored in the reading history memory | storage part by the wireless tag reading process of a wireless tag communication apparatus, when two types of tags remove | deviate from the inside of the communication area | region of a wireless tag communication apparatus. It is. The reading history information update processing for updating the reading history information stored in the reading history storage unit in the wireless tag reading processing of the wireless tag communication device when two types of tags are removed from the communication area of the wireless tag communication device is completed. It is a figure which shows reading history information at the time. It is a figure for demonstrating the reading process of the wireless tag by the binary tree system of a prior art.

Explanation of symbols

100 PC
DESCRIPTION OF SYMBOLS 110 RFID tag communication apparatus 120,121,122,123,300 RFID tag 130 Communication possible area 200 Communication antenna 201 Transmission / reception part 202 Tag information storage part 203 Mask value storage part 204 Reading history storage part 205 Reading order storage part 206 Mask value creation Unit 207 Reading result determination unit 208 PC command processing unit 209 PC communication control unit 301 Antenna unit 302 Transmission / reception unit 303 Storage unit 304 Control unit 400, 1200, 1700 Wireless tag ID list 900, 1400, 2000 Reading history information 1100, 1600 , 1800 Reading order information

Claims (14)

A wireless tag communication device that performs predetermined information processing by performing wireless tag reading processing representing transmission / reception of information wirelessly with a wireless tag,
A reading unit that creates optimized reading order information from the previous reading result of the wireless tag reading process and performs the wireless tag reading process according to the reading order information,
The reading unit creates optimized reading order information again from the current reading result of the wireless tag reading process, and reads the next wireless tag reading based on the reading order information generated from the result of the current wireless tag reading process. A wireless tag communication device characterized by performing processing. The reading means includes
A transmission / reception control means for controlling communication with the wireless tag;
Mask value creating means for creating a mask value to be set in a transmission signal in order to prevent collision of response waves from the wireless tag;
Tag information storage means for storing information of a wireless tag received by communication with the wireless tag;
A reading history storage unit that stores reading history information including a mask value specified when reading the wireless tag and a reading result when reading is performed by specifying the mask value;
Reading result determination means for determining the type of reading result;
Reading history information management means for managing reading history information stored in the reading history storage means in order to create reading order information indicating the order of transmission at the time of the next reading;
The wireless tag communication device according to claim 1, further comprising: a reading order information storage unit that stores the reading order information. The mask value creating means creates a mask value when the reading result determining means determines that the reading result is a collision at the end of reading of the wireless tag. Wireless tag communication device. The mask value creating means performs a mask value when the reading result determining means determines that the reading result is a collision when performing reading according to the reading order information stored in the previous reading order information storing means. The wireless tag communication device according to claim 2, wherein: The reading history information management unit updates the reading history information stored in the reading history information storage unit based on a determination result by the reading result determination unit when reading of the wireless tag is completed. The wireless tag communication device according to claim 2. The reading history information management unit updates reading history information stored in the reading history information storage unit in which the determination result by the reading result determination unit is determined to be a collision at the end of reading of the wireless tag. The wireless tag communication device according to claim 2. The reading history information management means, at the end of reading the wireless tag, about the reading history information stored in the reading history information storage means,
In the case where there are two reading history information for mask values that differ only in the value of the last bit, if the reading results of the reading history information are both unresponsive, the mask value in the reading history information is changed to the last of the current mask value. Update the bits of
When one of the reading results of the reading history information is the ID of the wireless tag and the other is no response, the mask value in the reading history information is updated to a value obtained by deleting the last bit of the current mask value. The wireless tag communication device according to claim 2. The reading history information management means reads the reading result of the reading history information stored in the reading history information storage means when reading according to the reading order information stored in the previous reading order information storage means. The wireless tag communication device according to claim 2, wherein updating is performed based on a determination result by the determination unit. The reading history information management means reads the reading result of the reading history information stored in the reading history information storage means when reading according to the reading order information stored in the previous reading order information storage means. The wireless tag communication device according to claim 2, wherein the wireless tag communication device is updated when it is determined that the reading result by the determination unit is a collision. The reading history information management means, when reading according to the reading order information stored in the previous reading order information storage means, about the reading history information stored in the reading history information storage means,
If there are two reading history information for mask values that differ only in the value of the last bit, and the reading results of the reading history information are both unresponsive, the mask value in the reading history information is set to the current mask value. Update the last bit to the deleted value,
When one of the reading results of the reading history information is the ID of the wireless tag and the other is no response, the mask value in the reading history information is updated to a value obtained by deleting the last bit of the current mask value. The wireless tag communication device according to claim 2. A wireless tag communication method for performing predetermined information processing by performing wireless tag reading processing representing transmission / reception of information wirelessly with a wireless tag,
Creating optimized reading order information from the previous reading result of the wireless tag reading process, and including a reading step of performing the wireless tag reading process according to the reading order information;
The reading step creates optimized reading order information again from the current reading result of the RFID tag reading process, and reads the next RFID tag based on the reading order information created from the result of the RFID tag reading process. A wireless tag communication method characterized by performing processing.   The program for making a computer perform the step contained in the radio | wireless tag communication method of Claim 11.   The computer-readable recording medium which recorded the program for making a computer perform the step contained in the radio | wireless tag communication method of Claim 11. A wireless tag communication device that performs predetermined information processing by performing wireless tag reading processing representing transmission / reception of information wirelessly with a wireless tag,
The reading order information optimized from the previous reading result of the wireless tag reading process is created, and the reading means for performing the wireless tag reading process according to the reading order information is integrated. An LSI that creates optimized reading order information from the reading result again, and performs the next RFID tag reading process based on the reading order information created from the result of the RFID tag reading process this time.

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