JP2007028274A - Reader/writer for wireless tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reader/writer for a wireless tag, capable of solving the problem of radio waves from a wireless tag cannot be received any longer, by being affected by the interference of radio waves emitted from respective reader/writers, without having to narrow the communication area of the reader/writer, when a plurality of reader/writers exist in the communicable area. <P>SOLUTION: The reader/writer for a wireless tag for communication with a wireless tag by radio is provided with a receiving circuit 103 for receiving signals of reader/writers other than a self-reader/writer 100 and a signal detection circuit 104 of the other reader/writers. The self-reader/writer 100 has a reader/writer control circuit 105 for making the self-reader/writer 100 go into the operation mode of the wireless tag, when the signal detection circuit 104 of the other reader/writers detects a signal of the reader/writers other than the self-reader/writer 100 and for making the self-reader/writer 100 start the operation mode of a normal reader/writer, when the signal detection circuit 104 does not detect the signal of the reader/writers, other than the self-reader/writer 100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reader / writer for a wireless tag that wirelessly communicates data with a wireless tag.

  The wireless tag reader / writer can transmit / receive data to / from a wireless tag including an IC chip and an antenna capable of storing information. This reader / writer is a system that can be detected by a collision prevention algorithm even when there are a plurality of wireless tags. However, when there are a plurality of reader / writers in the communicable area, the radio wave from the wireless tag cannot be received due to the influence of the radio wave emitted from each reader / writer. Patent Document 1 discloses a method for preventing radio wave interference by reducing the transmission power level when radio wave interference between reader / writers is detected and avoiding radio wave interference. Also, Patent Document 2 discloses a method for changing the frequency of communication in order to avoid radio wave interference.

  FIG. 4 is an explanatory diagram of an embodiment of a reader / writer according to a method for preventing radio wave interference between reader / writers of Patent Document 1. Reference numeral 100 denotes an own reader / writer, 101 denotes an antenna, 102 denotes a transmission circuit, 105 denotes a control circuit, 106 denotes a transmission circuit with an output adjustment function, and 107 denotes an inter-reader / writer interference detection circuit. When the receiving circuit 103 receives a reply signal from the reader / writer 100 and a transmission signal from another reader / writer via the antenna 101, the reader / writer interference detection circuit 107 detects radio wave interference, and the reader / writer In response to an instruction from the interfering interference detection circuit 107, the output is reduced by the transmission circuit 106 with an output adjustment function, and radio waves are transmitted again, thereby preventing radio wave interference.

JP 2003-216911 A JP 2000-4183 A

  The reader / writer of Patent Document 1 described above has a problem in that the communication function of the reader / writer 100 is shortened by operating the adjustment function for reducing the output, and the wireless tag that has been recognized so far cannot be recognized. It was.

  In addition, the method of changing the frequency at the time of radio wave interference described in Patent Document 2 described above has a complicated circuit for changing the frequency, so that the frequency after the change does not coincide with each other again to cause radio wave interference again. There is a problem that an additional control means is required.

  The present invention has been made to solve the above-described problems, and its technical problem is that when there are a plurality of reader / writers in an area where communication is possible, each reader / writer can be communicated without narrowing the communication area. It is an object of the present invention to provide a wireless tag reader / writer that solves the problem of being unable to receive radio waves from a radio tag due to the influence of radio waves emitted from a writer.

  According to a first aspect of the present invention, there is provided a wireless tag reader / writer that wirelessly communicates data with a wireless tag, comprising: a means for receiving a signal from a reader / writer other than the reader / writer; When the signal of the other reader / writer is detected by the detecting means, the own reader / writer enters an operation mode as a wireless tag, and when the signal of the other reader / writer is not detected, the own reader / writer This is a RFID tag reader / writer provided with reader / writer control means for entering an operation mode of the reader / writer.

  According to a second aspect of the invention for achieving the above object, when the signal of the other reader / writer is detected during communication with the wireless tag, the detection and control of the wireless tag that can be detected by the reader / writer are all completed. After that, the other reader / writer is notified of the end of the processing in the own reader / writer, and the reader / writer control means for controlling the own reader / writer to enter the operation mode as a wireless tag is provided. It is a reader / writer.

  According to a third aspect of the invention for achieving the above object, when the signal of the other reader / writer is detected during communication with the wireless tag, the ID number or priority identification of the own reader / writer and the other reader / writer are compared. When the priority of the reader / writer is high, the processing of the reader / writer is continued, and when the priority of the other reader / writer is high, the reader / writer enters an operation mode as a wireless tag. This is a RFID tag reader / writer provided with a reader / writer control means for controlling as described above.

  According to the present invention, when the signal of the reader / writer other than the own reader / writer is detected by the detecting means by including the means for receiving and detecting the signal of the reader / writer other than the own reader / writer, If the reader / writer enters the operation mode of the wireless tag and does not detect any other reader / writer signals other than the reader / writer, the reader / writer has a reader / writer control means for entering the normal reader / writer operation mode. Even when the reader / writer exists, communication with each wireless tag can be performed without narrowing the communication area of the reader / writer. In the present invention, since an adjustment function for reducing output is not required, a phenomenon that the communication area of the reader / writer is narrowed does not occur.

  In addition, when a signal of another reader / writer is detected during communication with the wireless tag, after the detection and control of the wireless tag that can be detected by the own reader / writer are completed, the processing of the own reader / writer is completed by the other reader / writer. The reader / writer itself has a control means to enter the operation mode of the wireless tag, thereby preventing the interference of radio waves between the reader / writer by performing the original operation of the reader / writer alternately with a simple configuration. it can.

  Further, when a signal collision of the reader / writer is detected, the ID number or priority identification between the own reader / writer and the other reader / writer is compared, and if the priority of the own reader / writer is high, the processing of the own reader / writer is performed. If the priority of other reader / writers is high, the reader / writer itself has a control means to enter the operation mode of the wireless tag so that the original operation of the reader / writer can be performed alternately with a simple configuration. Interference of radio waves between reader / writers can be prevented, and reading rights (reader / writer rights) can be changed by setting importance.

  As a result, when there are multiple reader / writers in the communicable area, radio waves from the wireless tag are affected by the interference of radio waves emitted from each reader / writer without narrowing the communication area of the reader / writer. It is possible to provide a reader / writer for a wireless tag that solves the problem of not receiving the signal.

  A wireless tag reader / writer according to the best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram showing Embodiment 1 of a reader / writer for a wireless tag according to the present invention. FIG. 2 is a diagram for explaining the operating state of the RFID tag reader / writer according to the present invention. FIG. 3 is a diagram for explaining an operation state of the RFID tag reader / writer according to the second embodiment of the present invention.

  As shown in FIG. 1, the reader / writer for a wireless tag according to the present invention includes a transmission circuit 102, a reception circuit 103 that receives a signal from a reader / writer other than the reader / writer, and another reader / writer signal detection circuit 104 that detects the signal. .

  As shown in FIG. 2, when the reader / writer A tries to start communication, the other reader / writer signal detection circuit 104 first checks whether “a signal from another reader / writer is being sent”. As a result, “when the signal from the reader / writer cannot be detected” is set to “enter the normal reader / writer operation as it is”, and when the signal from another reader / writer is detected, “the normal reader / writer operation” "Do not run".

  By providing such means, even when there are a plurality of reader / writers, communication between each wireless tag and the reader / writer can be performed without narrowing the communication area of the reader / writer. In the present invention, since an adjustment function for reducing output is not required, a phenomenon that the communication area of the reader / writer is narrowed does not occur.

  FIG. 2 illustrates a case where a signal of another reader / writer B that is already communicating with the wireless tag is detected. In this case, the reader / writer A determines that “another reader / writer already in operation exists”, and causes the control circuit 105 to “operate in the tag mode”. After the operation in the tag mode, the reader / writer A returns “its own ID number to the reader / writer B” in the same manner as other wireless tags. The reader / writer B detects “new wireless tag” and reads all “ID of detected wireless tag”. It can be recognized that the reader / writer A is based on the read ID. In this case, the IDs of all the wireless tags are continuously read, and the right to operate as a reader / writer, that is, the reader / writer right, is transferred to the reader / writer A when the processing and the like are completed, and the reader / writer B shifts to the tag mode. Upon receiving the reader / writer right, the reader / writer A changes from the tag mode to the reader / writer mode and operates as a normal reader / writer. By performing the original operation of the reader / writer alternately in this way, communication can be performed without being affected by the interference of radio waves emitted from each reader / writer even if there are multiple reader / writers without narrowing the communication area. It becomes possible.

  FIG. 3 illustrates a case where the reader / writer B detects the presence of the reader / writer A. If the reader / writer A and reader / writer B look at the priorities or ID numbers preliminarily discussed and the reader / writer (reader / writer B) is high, “continue processing in the reader / writer” and other readers When the writer (reader / writer A) is high, the reader / writer right is transferred to the reader / writer A, and the tag mode is entered so that the wireless tag operates. Even in this case, the original operation of the reader / writer is performed alternately, so that communication is not affected by the interference of radio waves emitted from each reader / writer even if there are multiple reader / writers without narrowing the communication area. Is possible.

  As a result, when there are multiple reader / writers in the communicable area, radio waves from the wireless tag are affected by the interference of radio waves emitted from each reader / writer without narrowing the communication area of the reader / writer. It is possible to provide a reader / writer for a wireless tag that solves the problem of not receiving the signal.

1 is a diagram showing Embodiment 1 of a wireless tag reader / writer according to the present invention. FIG. 6A and 6B illustrate an operation state of a wireless tag reader / writer according to the present invention. 8A and 8B illustrate an operation state of a wireless tag reader / writer according to a second embodiment of the present invention. Explanatory drawing of the Example of the reader / writer by the prevention method of the radio wave interference between the reader / writer of patent document 1. FIG.

Explanation of symbols

100 own reader / writer 101 antenna 102 transmitting circuit 103 receiving circuit 104 other reader / writer signal detecting circuit 105 control circuit 106 transmitting circuit with output adjusting function 107 inter-reader / writer interference detecting circuit

Claims (3)

  A wireless tag reader / writer that wirelessly communicates data with a wireless tag includes means for receiving a signal of a reader / writer other than the reader / writer and a means for detecting the signal, and the signal of the other reader / writer is detected by the detecting means. In this case, the reader / writer enters the operation mode as a wireless tag, and if the signal of the other reader / writer is not detected, the reader / writer has reader / writer control means for entering the normal reader / writer operation mode. A reader / writer for a wireless tag, characterized in that   When the signal of the other reader / writer is detected during communication with the wireless tag, after the detection and control of the wireless tag that can be detected by the own reader / writer are all completed, the other reader / writer 2. The reader / writer for a wireless tag according to claim 1, further comprising reader / writer control means for controlling that the reader / writer is in an operation mode as a wireless tag.   When the signal of the other reader / writer is detected during communication with the wireless tag, the ID of the reader / writer and the reader / writer are compared with each other, and the priority of the reader / writer is high. The reader / writer is provided with reader / writer control means for controlling the reader / writer to enter an operation mode as a wireless tag when the priority of the other reader / writer is high. The reader / writer for a wireless tag according to claim 1.

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