JP2009169544A - Data reading device and data reading method for data reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly achieve recovery processing at a high speed against error generation when performing the communication of data whose data length is long in a data reading device. <P>SOLUTION: In the data reading device 1 for reading data from an IC tag 20, a reception part 41 receives data from an IC tag 20, and an error detection/error position detection part 7 performs prescribed error detection processing to the received data, and when detecting any error in the data, specifies and outputs the error detection position where the error has been detected in the data, and a retransmission control part 6 inputs the error detection position from the error detection/error position detection part 7, and generates a retransmission request command to request the transmission of partial data from the error detection position to the final position of the data to the IC tag 20, and a transmission part 3 transmits a retransmission request command generated by the retransmission control part 6 to the IC tag 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data reading device that reads data from a communication device such as an IC tag and a data reading method of the data reading device.

  In the prior art, automatic recognition (RFID: Radio Frequency Identification) by non-contact data communication is performed during individual management of items and entrance / exit management by a computer. In automatic recognition (RFID) by non-contact data communication, for example, an IC (Integrated Circuit) tag in which a unique ID (identification) is written is attached to an identification object (article or person) that is a target of individual management or entrance / exit management. Keep it. The data reading device is installed at, for example, a gate (entrance, gate, etc.) or a side door. Therefore, when an identification target or the like equipped with an IC tag passes through the gate or side of the door, the data reading device installed on the side of the gate or door supplies power to the IC tag using radio waves. At the same time, a read command for reading the unique ID from the IC tag is transmitted.

  In the IC tag, a built-in silicon chip is driven by radio waves from the data reading device. The IC tag uses, for example, information stored in the IC tag such as a unique ID in response to a read command from the data reader, with or without reflection on radio waves emitted from the data reader. Response. The data reader identifies the presence or absence of a reflected wave that is a response from the IC tag, and reads information stored in the IC tag such as a unique ID.

  The IC tag has, for example, a memory area (also referred to as user memory) that can be rewritten by the user in addition to the unique ID area. The data length of the data stored in the user memory is longer than the data length of the unique ID. For this reason, when the data reading device reads all data stored in the user memory of the IC tag with a single command, the frequency of occurrence of errors in the read data increases.

In order to avoid the above problems, the conventional data reader divides the data to be read into a plurality of small packets, and sequentially reads each packet with a plurality of transmission request commands. In the conventional data reading method of the data reading apparatus, an error during packet reading performs a recovery process for the occurrence of the error by requesting retransmission of the packet in which the error has occurred.
JP 2003-296664 A

  However, in the data reading method of the conventional data reading device, when the data to be read is divided into small packets, it is added to the transmission command data at the time of command transmission for reading each packet and the response (packet) from the IC tag Information such as the return preamble and CRC that are displayed as overhead, and there is a problem that high-speed data reading cannot be performed.

  The present invention has been made to solve such a problem, and the data reading device performs communication of data with a long data length, and error when performing communication of data with a long data length. The purpose is to perform high-speed recovery processing against occurrence.

A data reading apparatus according to the present invention includes:
A data reading device that communicates with a communication device including a memory for storing data and reads data from the communication device,
A receiving unit for receiving the data from the communication device by a receiving device;
A predetermined error detection process for detecting an error in the data is performed on the data received by the receiving unit by the processing device. When an error is detected in the data, an error is detected in the data. An error detection / error position detection unit for specifying the error detection position by the processing device and outputting the error detection position;
Retransmission request that inputs the error detection position from the error detection / error position detection unit and requests the communication device to transmit partial data from the error detection position to the final position of the data in the data A retransmission control unit that generates a command by the processing device;
And a transmission unit that transmits the retransmission request command generated by the retransmission control unit to the communication device by the transmission device.

According to the present invention, in the data reading device that reads data from the communication device, the reception unit receives the data from the communication device, and the error detection / error position detection unit performs a predetermined error detection process on the received data. When an error is detected in the data, the error detection position where the error is detected in the data is specified and output, and the retransmission control unit determines the error detection position from the error detection / error position detection unit. Input, generate a retransmission request command for requesting the communication device to transmit partial data from the error detection position to the final position of the data, and the transmission unit generates a retransmission request command generated by the retransmission control unit Is transmitted to the communication device,
For example, even when an error occurs during reception of data to be read by the data reading device, it is possible to request retransmission of data from the position where the error is detected, thereby improving the processing speed of the data reading device. There is an effect that can be.

  FIG. 1 is a diagram illustrating an example of hardware resources of the data reading device 1 according to the first embodiment.

  In FIG. 1, the data reading apparatus 1 includes a CPU 911 (also referred to as a central processing unit, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, and a processor) that executes a program. The CPU 911 includes a ROM 913, a RAM 914, a communication board 915 (an example of a communication device, a transmission device, and a reception device), a display device 901, a keyboard 902, a mouse 903, an FDD904, a CDD905, a printer device 906, a scanner device 907, via a bus 912. It is connected to a magnetic disk device 920 and controls these hardware devices. Instead of the magnetic disk device 920, a storage device such as an optical disk device or a memory card read / write device may be used.

The RAM 914 is an example of a volatile memory. The storage media of the ROM 913, the FDD 904, the CDD 905, and the magnetic disk device 920 are an example of a nonvolatile memory. These are examples of a storage device or a storage unit.
The communication board 915, the keyboard 902, the scanner device 907, the FDD 904, and the like are examples of an input unit and an input device.

  Further, the communication board 915, the display device 901, the printer device 906, and the like are examples of an output unit and an output device.

  Although not shown, the communication board 915 is connected to a facsimile machine, a telephone set, a LAN, and the like. The communication board 915 may be connected not only to the LAN but also to a WAN (wide area network) such as the Internet or ISDN.

  The magnetic disk device 920 stores an operating system 921 (OS), a window system 922, a program group 923, and a file group 924. The programs in the program group 923 are executed by the CPU 911, the operating system 921, and the window system 922.

  The program group 923 stores programs for executing functions described as “˜unit” and “˜means” in the description of the embodiments described below. The program is read and executed by the CPU 911.

  The file group 924 includes information, data, signal values, variable values, and parameters that are described as “determination results of”, “calculation results of”, and “processing results of” in the description of the embodiments described below. Are stored as items “˜file”, “˜database”, and “˜data”. “˜file”, “˜database”, and “˜data” are stored in a recording medium such as a disk or a memory. Information, data, signal values, variable values, and parameters stored in a storage medium such as a disk or memory are read out to the main memory or cache memory by the CPU 911 via a read / write circuit, and extracted, searched, referenced, compared, Used for CPU operations such as calculation, calculation, processing, output, printing, and display. Information, data, signal values, variable values, and parameters are temporarily stored in the main memory, cache memory, and buffer memory during the CPU operations of extraction, search, reference, comparison, operation, calculation, processing, output, printing, and display. Is remembered.

  In addition, the arrows in the flowcharts described in the following description of the embodiments mainly indicate input / output of data and signals. The data and signal values are the RAM 914 memory, the FDD 904 flexible disk, the CDD 905 compact disk, and the magnetic field. The data is recorded on a recording medium such as a magnetic disk of the disk device 920, another optical disk, a mini disk, or a DVD (Digital Versatile Disk). Data and signals are transmitted online via a bus 912, signal lines, cables, or other transmission media.

  In addition, what is described as “to part” in the description of the embodiment described below may be “to circuit”, “to device”, “to device”, “means”, and “to step”. ”,“ ˜procedure ”, or“ ˜processing ”. That is, what is described as “˜unit” may be realized by firmware stored in the ROM 913. Alternatively, it may be implemented only by software, only hardware such as elements, devices, substrates, wirings, etc., or a combination of software and hardware, and further a combination of firmware. Firmware and software are stored as programs in a recording medium such as a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD. The program is read by the CPU 911 and executed by the CPU 911. That is, the program causes the computer to function as “to part” described below. Alternatively, the procedure or method of “to part” described below is executed by a computer.

Embodiment 1 FIG.
In the first embodiment, a data reading device 1 that communicates with an IC tag 20 (an example of a communication device) including a memory for storing data and reads data from the IC tag 20 will be described.

  FIG. 2 is a diagram illustrating a configuration of the data reading device 1 of the RFID system 800 according to the first embodiment. The RFID system 800 according to the first embodiment includes a data reading device 1, a computer 500 that controls the data reading device 1, and an IC tag 20 from which the data reading device 1 reads data. The data reading device 1 is instructed to read data stored in the memory held by the IC tag 20 from the computer 500 that controls the data reading device 1 (data reading instruction). Reading is performed, and the read data is transmitted to the computer 500 as a data reading result.

  An outline of a block configuration and a block function of the data reading apparatus 1 according to the first embodiment will be described with reference to FIG.

  In FIG. 2, the data reader 1 includes a transmission control unit 2, a transmission unit 3, a reception processing unit 4, a reception control unit 5, a retransmission control unit 6, a transmission antenna 10a, and a reception antenna 10b. I have.

  The transmission control unit 2 creates a command (also referred to as a command series) to be transmitted to the IC tag 20 (an example of a communication device). The transmission control unit 2 uses a processing device to generate a command (an example of a transmission request command) for executing the data read instruction in accordance with the data read instruction input from the computer 500.

  The transmission unit 3 transmits a command (an example of a transmission request command) generated by the transmission control unit 2 to the IC tag 20. In addition, a command (an example of a retransmission request command) generated by a retransmission control unit 6 described later is transmitted to the IC tag 20.

  The reception processing unit 4 receives response data from the IC tag 20 as a response to the command transmitted from the transmission unit 3 by the reception device, and performs processing such as error check on the received response data by the processing device. Processing corresponding to the result such as check is performed on the response data. Details of the reception processing unit 4 will be described later.

  The reception control unit 5 receives a reception result (response data) from the reception processing unit 4 in the response data received from the IC tag 20 when no error is detected by the reception processing unit 4, and sends it to the computer 500 as a data read result. In addition to outputting, the activation of the next command transmission (transmission request command transmission) is controlled.

  If the reception processing unit 4 detects an error in the response data received from the IC tag 20, the retransmission control unit 6 receives the error detection result and the error detection position in the response data from the reception processing unit 4, and retransmits the command. Control transmission.

  The data reader 1 is connected to a transmission antenna 10a that transmits radio waves to the IC tag and a reception antenna 10b that receives response data from the IC tag.

  The reception processing unit 4 includes a reception unit 41, an error detection / error position detection unit 7, a reception buffer unit 8, a reception buffer 81, and an optimum reception data length determination unit 9.

  The reception unit 41 receives response data from the IC tag 20 (communication device) by the reception antenna 10b (reception device) as a response to the command transmitted by the transmission unit 3. The error detection / error position detection unit 7 performs error detection and error position detection of response data from the IC tag 20. The reception buffer unit 8 temporarily stores response data from the IC tag 20 in the reception buffer 81. The optimum received data length determination unit 9 monitors the history of the error position information detected by the error detection / error position detection unit 7 in the response data, and determines the optimum response data length.

  Furthermore, the data reading function of each functional block in the data reading device 1 will be described in detail with reference to FIG.

  An instruction (data read instruction) for reading data stored in a memory (also referred to as user memory) included in the IC tag 20 is input from the computer 500 that controls the data reader 1 to the data reader 1. Is done.

  When a data read instruction is input from the computer 500, the transmission control unit 2 generates a command (an example of a transmission request command) for executing the data read instruction requested from the computer by the processing device. Control to transmit to the IC tag 20. The transmission control unit 2 generates the command and, at the same time, when the data length (response data length) of the response data to be received as the response data from the IC tag 20 is known in advance, the response data length is received by the reception processing unit 4. And output (transmit) to the reception control unit 5. The case where the response data length is known in advance is, for example, the case where the response data length of the response data to be received is indicated by the data read instruction from the computer input by the transmission control unit 2.

  The transmission unit 3 modulates the command generated by the transmission control unit 2 and controlled to be transmitted to the IC tag 20, and transmits the modulated command to the IC tag 20. The command modulated by the transmission unit 3 is emitted as a radio wave to the IC tag 20 via the transmission antenna 10a (an example of a transmission device).

  The IC tag 20 demodulates the radio wave (command) emitted from the transmission antenna 10a, analyzes the command, and returns a response data radio wave as a response (response) according to the emitted command.

  The receiving unit 41 receives a radio wave that is response data from the IC tag 20 by the receiving antenna 10b (an example of a receiving device), and demodulates the radio wave that is the received response data.

  The error detection / error position detection unit 7 receives the response data (an example of data) demodulated by the reception unit 41, and performs an error detection process (an example of a predetermined error detection process) on the input response data.

  Here, a specific example of error detection processing (predetermined error detection processing) performed on the response data input by the error detection / error position detection unit 7 will be described. FIG. 11 is a diagram illustrating a normal frequency pattern of a bit string as a result of data encoding in wireless communication in the RFID system 800 according to Embodiment 1. The wireless communication in the RFID system 800 according to Embodiment 1 is wireless communication based on the wireless interface specification standardized by EPC Global, for example. In this case, the normal frequency pattern of the bit string as a result of data encoding is the frequency pattern shown in FIG.

  In the case of “00”, the error detection / error position detection unit 7 determines that the error is correct when the frequency pattern of the bit string is “HLHL”, but, for example, is “HHHL”. Alternatively, in the case of “01”, the error detection / error position detection unit 7 determines that the error is correct when the frequency pattern of the bit string is “LHLL”, but, for example, is “LHHL”. . As described above, the error detection / error position detection unit 7 performs error detection processing as an error by detecting a pattern other than the frequency pattern of the bit string shown in FIG. 11, for example, as the predetermined error detection processing.

  When the error detection / error position detection unit 7 detects an error in the response data, the error detection position where the error is detected in the response data is specified by the processing device and is output to the retransmission control unit 6. . The error detection / error position detection unit 7 outputs an error result report indicating that an error has been detected in the response data to the reception buffer unit 8.

  When no error is detected in the response data, the error detection / error position detection unit 7 automatically adds a CRC (Cyclic Redundancy Check) to the response data from the IC tag 20. Based on the CRC check. At this time, the validity check process of the response data may be performed based on check data (described later) included in the response data. Here, the CRC automatically added to the response data is a kind of error detection code for detecting continuous errors added to the communication data by the conventional communication method.

  When the error detection / error position detection unit 7 determines that the response data is not valid as a result of performing CRC check processing or validity check processing using the check data on the response data, the reception buffer unit 8, an error result report indicating that the response data is not valid data is output.

  The reception buffer unit 8 temporarily stores the response data demodulated by the reception unit 41 in the reception buffer 81 (an example of a storage device). The reception buffer unit 8 receives the error result report for the response data from the error detection / error position detection unit 7 and when the response data has reached the response data length instructed by the transmission control unit 2, the reception control unit 5, the contents of the reception buffer 81 (that is, response data) are output. The error result report here includes an error report by the above-described error detection process (an example of a predetermined error detection process), an error report by a CRC check process or a validity check process by check data, and the like.

  The reception control unit 5 compares the data length of the response data input and sent from the reception buffer unit 8 with the response data length instructed from the transmission control unit 2 by the processing device, and when they match, The response data is output as a read result to the computer 500 that controls the data reading apparatus 1.

  The retransmission control unit 6 inputs the error detection position in the response data from the error detection / error position detection unit 7 and sends the response data from the error detection position in the response data to the IC tag 20 (communication device). The processing device generates a retransmission request command for requesting transmission of partial data that is a portion up to the final position of. For example, when the retransmission control unit 6 determines that the reception of the response data up to the final position is completed (that is, the response from the IC tag 20 is completed), the error detection / error position detection unit 7 reports the response data. Command to calculate the length of the unread area from the detected error detection position and request transmission of data (partial data) of the length of the unread area from the error position in the response data (retransmission request command ) And output to the transmitter 3. The unread area length data (partial data) is data from the error detection position reported from the error detection / error position detection unit 7 in the response data to the final position of the response data.

  The transmission unit 3 modulates the retransmission request command generated by the retransmission control unit 6 and transmits it to the IC tag 20. The retransmission request command modulated by the transmission unit 3 is emitted as a retransmission request command radio wave to the IC tag 20 via the transmission antenna 10a.

  The IC tag 20 demodulates the radio wave emitted from the transmission antenna 10a (retransmission request command for requesting transmission of partial data), analyzes the command (retransmission request command for requesting transmission of partial data), and analyzes the command. A partial data radio wave is returned as a response (that is, partial data) in response to a command (retransmission request command for requesting transmission of partial data).

  The receiving unit 41 receives the radio wave of the partial data from the IC tag 20 (that is, response data received as a response to the retransmission request command) by the receiving antenna 10b (an example of a receiving device), and receives the partial data from the IC tag 20 Demodulate the radio waves.

  The error detection / error position detection unit 7 receives the partial data demodulated by the reception unit 41 and performs error detection processing (an example of predetermined error detection processing) on the input partial data.

  When the error detection / error position detection unit 7 detects an error in the partial data, the error detection position where the error is detected in the partial data is specified by the processing device and is output to the retransmission control unit 6. . The error detection / error position detection unit 7 outputs an error result report indicating that an error has been detected in the partial data to the reception buffer unit 8.

  The reception buffer unit 8 temporarily stores the partial data demodulated by the reception unit 41 in the reception buffer 81 (an example of a storage device). For example, the reception buffer unit 8 stores the partial data in a region different from the response data previously received from the IC tag 20 and stored in the reception buffer 81. Alternatively, the reception buffer unit 8 may overwrite and store the partial data from the error detection position of the response data already stored in the reception buffer 81.

  When no error is detected in the partial data, the error detection / error position detection unit 7 performs CRC check processing based on the CRC automatically added to the partial data from the IC tag 20 to verify the validity of the partial data. Check. If the error detection / error position detection unit 7 performs the CRC check process on the partial data and determines that the partial data is not valid data, the partial data is sent to the reception buffer unit 8. Outputs an error result report indicating that the data is not valid.

  When the error detection / error position detection unit 7 performs CRC check processing on the partial data and determines that the partial data is valid data, the error detection / error position detection unit 7 holds the partial data in the reception buffer 81. Of the response data (that is, the response data received as a response to the first transmission request command), and the data obtained by combining the response data from the head position to the position before the error detection position and the partial data. Data read from 20 (communication device). For example, the error detection / error position detection unit 7 detects an error in the response data held in the reception buffer 81 by the reception buffer unit 8 (that is, response data received as a response to the first transmission request command). Data can be combined by overwriting partial data (that is, response data received as a response to the retransmission request command) from the error detection position.

  As described above, when an error is detected in the partial data, the error detection / error position detection unit 7 outputs the error detection position in the partial data to the retransmission control unit 6 again. The error detection / error position detection unit 7 outputs an error result report indicating that an error has been detected in the partial data to the reception buffer unit 8. Then, the retransmission control unit 6 generates a retransmission request command (second time) for requesting retransmission of unread data from the error detection position in the partial data, and the transmission unit 3 A retransmission request command (second time) is transmitted to the IC tag 20.

The data reader 1 determines that the response data held in the reception buffer 81 is valid data without error detection, and determines that the response data length instructed from the transmission control unit 2 has been reached. Until this is the case, the processing described above may be repeated to request retransmission. Alternatively, the data reading device 1 may set an upper limit of the number of times of repeating the process for requesting retransmission. If you set a limit,
The optimum received data length determination unit 9 monitors information on the error detection position specified by the error detection / error position detection unit 7, and calculates the optimum partial data length (data length of data to be retransmitted) by the processing device. Then, the calculated optimum partial data length (data length of data to be retransmitted) is output to the retransmission control unit 6 to instruct the optimum partial data length.

  The retransmission control unit 6 generates a command (retransmission request command) based on the optimum partial data length (data length of data to be retransmitted) designated by the optimum received data length determination unit 9.

  FIG. 3 is a configuration diagram of the memory 21 provided (held) in the IC tag 20 (an example of a communication device) according to the first embodiment. A configuration diagram of the memory 21 included in the IC tag 20 (an example of a communication device) according to the first embodiment will be described with reference to FIG.

  In FIG. 3, the memory 21 held by the IC tag 20 is a memory that can be rewritten by the user. The memory 21 is divided into blocks 0 to N. In the block x (x is an integer from 0 to N), data x and check data x of the block x are stored. That is, the block x stores data x of the block x and check data x stored after the data x of the block x. That is, the block data x which is all data stored in the block x is composed of the data x of the block x and the check data x added after the data x of the block x.

  The check data x is data calculated for performing a validity check process for the data x of the block x. The generation rule of the check data x is not particularly defined as long as it is a rule that can detect a bit error in the data x of the block x. The generation rule of the check data x may be, for example, a CRC16 generation rule as described in ISO / IEC 18000-6C.

  FIG. 4 shows a communication operation when the data reading device 1 reads block data x including check data x from the IC tag 20 and no error is detected in the block data x as a result of a predetermined error detection process. FIG.

  In FIG. 4, the data reading device 1 reads the block data x (an example of the response data described above) stored in the memory 21 of the IC tag 20 described above. The block data x is composed of data x of the block x and check data x.

  In the data reading device 1, the check data calculated for the transmission control unit 2 to perform validity check processing of the data x (an example of the first data) of the block x and the data x of the block x from the IC tag 20. A transmission command C1 (an example of a transmission request command) for reading block data x (an example of data) including x (an example of check data) is generated. Then, the transmission unit 3 transmits a transmission command C1 to the IC tag 20 (S1). The receiving unit 41 receives the reception data D1 including the block data x as a response to the transmission command C1 (S2).

  FIG. 5 is a diagram showing a format of the reception data D1. As shown in FIG. 5, the received data D1 is composed of a return preamble 51, a data part 52, and a CRC 53 by a conventional communication method. Therefore, the reception data D1 in FIG. 4 has the return preamble 51 added before the block data x, the CRC 53 added after the block data x, and the block 52 which is the reading target in the data portion 52. As described above, the block data x is composed of the data x of the block x and the check data x. Accordingly, the received data D1 is configured in the order of the return preamble 51, the data x (data part 52) of the block x, the check data x, and the CRC 53.

  Returning to FIG. 4, in the data reading device 1, the error detection / error position detection unit 7 performs error detection processing (an example of predetermined error detection processing) on the received reception data D <b> 1, and the reception buffer unit 8 The block data x is read from the received reception data D 1 and stored in the reception buffer 81.

  At this time, the reception buffer unit 8 may store the reception data D1 as it is in the reception buffer 81, or reads the block data x from the reception data D1 and stores the block data x in the reception buffer 81. Also good.

  The error detection / error position detection unit 7 checks if no error is detected in the received data D1 (in the block data x) as a result of the error detection process (an example of a predetermined error detection process). A communication error is confirmed by the block data x including the data x and the CRC 53 automatically added at the time of response communication from the IC tag 20. That is, the error detection / error position detection unit 7 compares the CRC calculated from the block data x including the check data x with the CRC 53 included in the reception data D1 from the IC tag 20 by the processing device. When the error detection / error position detection unit 7 determines that the CRC calculated from the block data x including the check data x matches the CRC 53 included in the reception data D1 from the IC tag 20, It is determined that the block data x including the check data x is guaranteed to be valid response data without error. In the data reading device 1, the reception buffer unit 8 outputs block data x guaranteed as valid response data from the reception buffer 81 to the reception control unit 5. In this case, the reception buffer unit 8 may discard the check data x.

  Alternatively, when the error detection / error position detection unit 7 does not detect an error in the received data D1, the data reading device 1 is based on the check data x included in the block data x instead of the validity check by CRC. A validity check process may be performed. In the data reading device 1, the error detection / error position detection unit 7 determines whether the data x (first data) of the block x is valid data based on the check data x included in the block data x. When the data check process is performed by the processing device and it is determined that the data x (first data) of the block x is valid data, the block data x is read as data read from the IC tag (communication device). Output to unit 5. For example, the error detection / error position detection unit 7 compares the check data calculated from the data x of the block x of the block data x with the check data x included in the received reception data D1 by the processing device. And so on. For example, the error detection / error position detection unit 7 determines that the check data calculated from the data x of the block x in the block data x matches the check data x included in the received reception data D1. In this case, it is determined that the data x of the block x out of the block data x is guaranteed to be valid response data without error.

  FIG. 6 shows a communication operation when the data reading device 1 reads the block data x including the check data x from the IC tag 20 and detects an error in the block data x as a result of a predetermined error detection process. FIG.

  In FIG. 6, the data reading device 1 reads block data x (an example of the response data described above) stored in the memory 21 of the IC tag 20 described above. The block data x is composed of data x of the block x and check data x.

  In the data reading device 1, the check data calculated for the transmission control unit 2 to perform validity check processing of the data x (an example of the first data) of the block x and the data x of the block x from the IC tag 20. A transmission command C1 for reading block data x (an example of data) including x is generated. Then, the transmission unit 3 transmits a transmission command C1 to the IC tag 20 (S10: first transmission command). The reception unit 41 receives the reception data D1 including the block data x as a response to the transmission command C1 (S11: first reception data D1).

  In the data reading device 1, the reception buffer unit 8 reads the block data x from the received reception data D1, stores the block data x in the reception buffer 81, and the error detection / error position detection unit 7 receives the data. An error detection process (an example of a predetermined error detection process) is performed on the block data x of the received data D1.

  At this time, the reception buffer unit 8 may store the reception data D1 as it is in the reception buffer 81, or reads the block data x from the reception data D1 and stores the block data x in the reception buffer 81. Also good.

  The error detection / error position detection unit 7 performs error detection processing (predetermined error detection processing) on block data x (data) including data x (first data) and check data x of the block x, When an error is detected in the block data x, an error detection position (an example of an error position) where the error is detected in the block data x is specified and output to the retransmission control unit 6. The error detection / error position detection unit 7 detects an error in the data x of the block x (error position) when an error is detected in the data x (first data) of the block x. May be specified and output to the retransmission control unit 6.

  The re-transmission control unit 6 inputs the error detection position in the block data x from the error detection / error position detection unit 7, and sends the final check data x from the error detection position in the block data x to the IC tag 20. The processing device generates a transmission command C2 (an example of a retransmission request command) that requests transmission of unread data (an example of partial data) up to a position (that is, the final position of the block data x). Then, the transmission unit 3 transmits a transmission command C2 (an example of a retransmission request command) to the IC tag 20 (S12: second transmission command).

  As a response to the transmission command C2, the reception unit 41 receives unread data (an example of partial data) from the error detection position in the block data x to the final position of the check data x (that is, the final position of the block data x). The received reception data D2 is received (S13: second reception data). The received data D2 from the IC tag 20 in response to the transmission command C2 includes a return preamble 51a, data from the error detection position to the final position of the check data x as the data part 52a (unread data (an example of partial data)), CRC 53a. It is configured.

  Next, in the data reading device 1, the error detection / error position detection unit 7 performs error detection processing (predetermined error detection processing) on the received data D2 in the same manner as the processing for the received data D1 received for the first time. Example).

  At this time, the reception buffer unit 8 reads unread data (partial data) from the received reception data D2 and processes the unread data in the reception buffer 81 in the same manner as the processing for the reception data D1 received for the first time. May be stored. At this time, the reception buffer unit 8 may store the unread data in an area different from the block data x received at the first time in the reception buffer 81. Alternatively, the reception buffer unit 8 may overwrite and store the unread data from the error detection position of the block data x received in the first time in the reception buffer 81. At this time, the reception buffer unit 8 may store the reception data D2 in the reception buffer 81 as it is.

  If no error is detected in the received data D2 as a result of the error detection process (an example of a predetermined error detection process), the error detection / error position detection unit 7 checks from the error detection position in the reception data D1. CRC check processing is performed by data up to data x (unread data (partial data)) and CRC 53a automatically added to the received data D2 as a response from the IC tag 20 (S14). Check. That is, the error detection / error position detection unit 7 calculates the CRC calculated from the unread data (partial data) included in the reception data D2 and the CRC 53a automatically added to the reception data D2 from the IC tag 20. The comparison is performed by the processing device. The error detection / error position detection unit 7 determines that the CRC calculated from the unread data (partial data) included in the reception data D2 matches the CRC 53a automatically added to the reception data D2. In this case, it is determined that unread data (partial data) included in the received data D2 is guaranteed to be legitimate data without error (unread data (partial data) (S14: CRC for the received data D2). Check processing).

  In the data reading device 1, when the error detection / error position detection unit 7 determines that the unread data (partial data) included in the received data D2 is guaranteed to be valid data having no error, the block data Data obtained by combining the data from the first data position (start position) in x (data) to the position before the error detection position and unread data (partial data) as data read from the IC tag 20 is received. Output to the control unit 5.

  That is, in the data reading device 1, the error detection / error position detection unit 7 starts from the first reception data D1 stored in the reception buffer 81, from the first data position of the block data x to the position before the error detection position. The portion is extracted by the processing device, and unread data (partial data) is extracted by the processing device from the second received data D2 stored in the reception buffer 81. Then, the error detection / error position detection unit 7 and the portion of the block data x from the extracted reception data D1 from the first data position to the front of the error detection position and the unread data from the second reception data D2 ( The data of the block data x is reproduced by combining the two data (partial data) by the processing device (S15: reproduction of the block data x). At this time, the error detection / error position detection unit 7 stores the portion of the block data x of the first reception data D1 stored in the reception buffer 81 from the error detection position in the reception buffer 81. The unread data (partial data) of the second received data D2 is overwritten by the processing device, so that the portion from the first data position of the block data x from the received data D1 to the position before the error detection position and the second time Two pieces of data can be combined with unread data (partial data) from the received data D2.

  Next, in the data reading device 1, the error detection / error position detection unit 7 includes the data x (first data) of the block data x among the combined data based on the check data x included in the unread data (partial data). 1 is performed by the processing device (S16: legitimacy check processing using check data x), and data x (first data) of block x is legitimate. When it is determined that the data is data, the combined data is output to the reception control unit 5 as data read from the IC tag (communication device). For example, the error detection / error position detection unit 7 compares the check data calculated from the data x of the block x of the block data x with the check data x included in the received reception data D2 by the processing device. And so on. For example, the error detection / error position detection unit 7 determines that the check data calculated from the data x of the block x in the block data x matches the check data x included in the received reception data D2. In this case, it is determined that the data x of the block x out of the block data x is guaranteed to be valid response data without error.

  At this time, the second received data D2 is confirmed to be legitimate data without a communication error or the like by performing CRC confirmation (S14 in FIG. 6). However, it is guaranteed that the first received data D1 is legitimate data without a communication error, although there is no error detection by a predetermined error detection process from the head position of the block data x to the position before the error detection position. (Because the validity check processing such as CRC check processing is not performed). Therefore, conventionally, when an error is detected in the block data x, it is necessary to read the block data x again from the head position of the block data x. For this reason, conventionally, there has been a problem such as an increase in reading time during the data reading process. Alternatively, in the conventional data reader, in order to avoid re-reading of data having a long data length, the block data x is read by being divided into finer packets, so that command transmission or addition to individual packets is performed. It was necessary to withstand the increase in reading time due to the return preamble and CRC overhead.

  In the data reading apparatus 1 according to the present embodiment, check data is provided for each block data, so that the validity of the reproduced block data (received data) can be checked using the check data, and the read time Can be shortened.

  Further, in the data reading device 1 according to the present embodiment, even when an error occurs in data reading from the memory 21 held by the IC tag 20, the IC tag 20 may be requested to retransmit from the location where the error has occurred. The data can be reproduced, and the validity of the data reproduced by the check data can be guaranteed, so that the data reading time can be shortened.

Embodiment 2. FIG.
In the data reading device 1 according to the first embodiment, the case where the data read from the memory 21 of the IC tag 20 by the data reading device 1 is the block data x including the check data x has been described. In the second embodiment, while no error is detected in the received data, data that does not include the check data x of the block x (that is, the data x of the block x) is read. A data reader 1 that reads check data x of a block x in addition to data x of the remaining block x will be described.

  FIG. 7 is a diagram illustrating a communication operation when the data reading apparatus 1 according to the second embodiment reads data x of the block x not including the check data x from the IC tag 20 and no error is detected.

  In FIG. 7, the data reading device 1 makes a read request for data that does not include the check data x (that is, the data x of the block x) with the transmission command C1 (S20), receives the received data D1, and receives the data of the block x x is read (S21). The operation of the data reading device 1 at this time is the same as that of the first embodiment. However, the difference is that the data requested by the data reader 1 is the data x of the block x.

  In the data reading device 1 according to the second embodiment, the reception data D1 includes a return preamble 51, a data unit 52, and a CRC 53 as shown in FIG. The data part 52 stores data x of the block x that does not include the check data x.

In the data reading device 1 according to the second embodiment, when the error detection / error position detection unit 7 does not detect an error in the reception data D1, the block data x and the block data x are detected as in the first embodiment. The communication error is confirmed by the CRC that is automatically added to the received data D1, which is a response from the IC tag 20. About the correctness check process by CRC (CRC check process), the same process as described in the first embodiment is performed. The data reading device 1 compares the CRC generated from the data x of the block x with the CRC added to the reception data D1 which is a response from the IC tag 20, and if they match, the reception data The processing device determines that D1 is guaranteed to be valid response data without error.

  FIG. 8 is a diagram illustrating a communication operation when the data reading device 1 according to the second embodiment reads data x of the block x not including the check data x from the IC tag 20 and detects an error.

  In FIG. 8, the data reading device 1 according to the second embodiment makes a read request for data that does not include the check data x (that is, the data x of the block x) with the transmission command C1 (S30), and receives the reception data D1. The data x of the block x is read (S31). The operation of the data reading device 1 at this time is the same as that of the first embodiment. However, the difference is that the data requested by the data reader 1 is the data x of the block x.

  In the data reading device 1 according to the second embodiment, when the error detection / error position detection unit 7 detects an error in the received data D1, the error in the data x of the block x is the same as the operation of the first embodiment. The detection position is specified and output to the retransmission control unit 6.

  The retransmission control unit 6 inputs the error detection position in the data x of the block x from the error detection / error position detection unit 7 and checks the check data from the error detection position in the data x of the block x to the IC tag 20. The processing device generates a transmission command C2 (retransmission request command) for requesting data transmission up to the final position of x (that is, the final position of the block data x). Then, the transmission unit 3 transmits a transmission command C2 (retransmission request command) to the IC tag 20 (S32: second transmission command). At this time, unlike the transmission command C1 (transmission request command), the transmission command C2 (retransmission request command) instructs to read up to the check data x. The reception data D2 of the IC tag for the transmission command C2 includes a return preamble 51, data from the error detection position to the check data x (data portion 52), and CRC 53 (S33: second reception data D2).

  As in the first embodiment, in the data reading device 1 in the second embodiment, the error detection / error position detection unit 7 performs error detection processing (an example of predetermined error detection processing) on the received data D2. Do.

  If the error detection / error position detection unit 7 does not detect an error in the received data D2, the error detection / error position detection unit 7 converts the data x of the block x from the error detection position to the check data x. On the other hand, the communication error is confirmed by the CRC 53b automatically added to the response from the IC tag 20. That is, the error detection / error position detection unit 7 compares the CRC generated from the data from the error detection position of the data x of the block x to the check data x and the CRC 53b included in the reception data D2 from the IC tag 20. If they match, it is determined that the received data D2 is guaranteed to be legitimate received data with no error (S34: CRC check processing of received data D2).

  The data reading device 1 according to the second embodiment extracts from the first received data D1 a portion from the first data position (start position) of the data x of the block x to the position before the error detection position of the data x of the block x. A portion from the error detection position of the data x of the block x to the final position of the check data x is extracted from the second received data D2.

  The data reading device 1 in the second embodiment combines the two data and reproduces the data x of the block x (S35: reproduction of the block data x).

  Next, in the data reading device 1 according to the second embodiment, the error detection / error position detection unit 7 combines the check data x included in the reception data D2 based on the check data x as in the processing of the first embodiment. The processing device performs a validity check process to determine whether or not the data x of the block x in the processed data is valid data (S36: validity check process using the check data x), and the data x of the block x is valid. When it is determined that the data is data, the combined data is output to the reception control unit 5 as data read from the IC tag (communication device).

  As described above, in the data reading apparatus 1 according to the second embodiment, the check data x is not read while no error is detected in the received data, so that the reading time can be further shortened.

Embodiment 3 FIG.
FIG. 9 is a diagram showing a system configuration of an RFID system using the data reading device 1 according to the third embodiment. In FIG. 9, the same reference numerals are given to the constituent blocks having the same functions as the constituent blocks described in FIG. 2 of the first embodiment, and a part of the description is omitted.

  In FIG. 9, the data reading device 1 includes a transmission control unit 2, a transmission unit 3, a reception processing unit 4, a reception control unit 5, and a retransmission control unit 6, as in the first embodiment, and an IC tag 20 is connected to a transmission antenna 10 a that transmits radio waves to the reception antenna 10 b and a reception antenna 10 b that receives radio waves from the IC tag 20. Similarly to the first embodiment, the reception processing unit 4 includes an error detection / error position detection unit 7, a reception buffer unit 8, a reception buffer 81, and an optimum reception data length determination unit 9. The data reading device 1 according to the third embodiment is different from the first embodiment in that the error detection / error position detection unit 7 includes a reception data correction unit 11.

  The general operation of the data reading apparatus 1 according to the third embodiment is the same as the operation described in the first embodiment. However, since the operation when the error detection / error position detection unit 7 detects an error is different from that of the first embodiment, the operation of this portion will be described below.

  FIG. 10 is a diagram illustrating a communication operation between the data reading device 1 and the IC tag 20 when an error is detected in the received data received from the IC tag 20 according to the third embodiment.

  First, in S40, the data reading device 1 generates a transmission command C1 (transmission request command) for reading the block data x composed of the data x of the block x and the check data x from the IC tag 20, and transmits it to the IC tag. To do.

  In S41, the data reading device 1 receives the reception data D1 from the IC tag 20 as a response to the transmission command C1. In the data reading device 1, the error detection / error position detection unit 7 performs error detection processing (predetermined error detection processing) on the received data D1.

  In S42, when the received data correction unit 11 included in the error detection / error position detection unit 7 detects an error in the received data D1, 0 or 1 is substituted into the error detection bit position (to the error detection position in FIG. 10). 0/1), and the data correction (correction of data) of the error data of the data x of the block x is performed. For example, the received data correction unit 11 performs a process of substituting 0 when the bit of error data detected as an error is 1, and substituting 1 when the bit of error data detected as an error is 0, Perform error correction on error data. For example, when there are a plurality of error data detected as errors, the reception data correction unit 11 performs error correction on the plurality of error data.

  Next, in S43, the error detection / error position detection unit 7 uses the CRC 53c automatically added to the reception data D1 with respect to the reception data D1 (block data x) subjected to data correction. CRC check processing of block data x is performed. Alternatively, when no error is detected in the check data x, the error detection / error position detection unit 7 uses the check data x for the reception data D1 (block data x) subjected to data correction. The validity check processing of the data x of the block x may be performed.

  If the error detection / error position detection unit 7 determines that the received data D1 (block data x) is valid as a result of the CRC check process or the validity check process using the check data, the error detection / error position detection unit 7 converts the block data x to the IC tag. The data read from 20 (communication device) is output to the reception control unit 5.

  However, the error detection / error position detection unit 7 determines that the received data D1 (block data x) is not valid data as a result of CRC check processing or validity check processing using check data, or the check data x If CRC 53c contains an error, or if check data or CRC match occurs in a combination of a plurality of received data D1, the correctness of the corrected data cannot be guaranteed, so that it has been described in the first embodiment. Data is reproduced using a process for requesting retransmission.

  Here, the above-mentioned “when check data or CRC coincides with a combination of a plurality of received data D1” refers to the following cases, for example. When errors occur in a plurality of locations of the received data D1, 0 or 1 is entered in each error location and the data is corrected. Therefore, there are a plurality of candidates for the corrected received data D1. The confirmation of the plurality of corrected received data D1 candidates is performed by CRC check processing or validity check processing using check data as described above. At this time, since the original data (reception data D1) is several hundred bits, the check data is about 32 bits, and the CRC is 16 bits, so among the plurality of corrected reception data D1, the check data and CRC are used. There may be a plurality of received data D1 that pass the check. In this case, it is impossible to determine which correction data is correct among the plurality of corrected reception data D1 candidates, and the correctness cannot be guaranteed. Therefore, the process for requesting retransmission described in the first embodiment is used. To play back the data.

  In addition, in the data reading device 1 according to the third embodiment, when the number of detected bits is large, the processing time required for data correction increases, and therefore processing for requesting retransmission without performing data correction is performed. It may be used to reproduce data.

  That is, in the data reading apparatus 1 according to the third embodiment, the error detection / error position detection unit 7 (or the reception data correction unit 11 may be used) is the data of the block x in the reception data D1 (block data x). When an error is detected in x (first data), the error detection position where the error is detected in the data x of the block x is specified, and the error is detected in the data x of the block x Data correction is performed on the error data. Then, the error detection / error position detection unit 7 determines whether the data x (first data) of the block x is valid data based on the check data x for the block data x subjected to data correction. When the processing unit performs the property check process and determines that the data x of the block x is not valid data, the error detection position of the data x of the block x is output to the retransmission control unit 6.

  As described above, in the data reading device 1 according to the third embodiment, even when an error occurs in the data being read in the data reading from the memory 21 held by the IC tag 20, the error occurrence location is specified. The error data is corrected, and the correctness of the correction data can be guaranteed by the check data or CRC. For this reason, in the data reading apparatus 1 according to the third embodiment, even if an error occurs in the data being read, the reading time can be shortened without performing re-reading. Further, in the data reading apparatus 1 according to the third embodiment, when error data correction is incomplete (when check data or CRC includes an error, or when check data or CRC match occurs in a plurality of combinations). In this case, it is possible to guarantee the validity of the data without a significant increase in the reading time by performing a process for requesting retransmission.

  In the first to third embodiments, the data reading device 1 having the following characteristics has been described.

  The RFID system 800 described in the first to third embodiments includes an IC tag 20 that includes a memory 21 that can be rewritten by a user, divides the memory 21 into a plurality of blocks, and stores check data for each block. 20 is an RFID system 800 that reads out memory data held by the IC tag 20, and the data reading device 1 detects an error when receiving data from the IC tag 20. If an error is detected, the error detection / error position detection unit 7 detects the data position where the error was detected, and if an error is detected by the error detection and error position detection unit, retransmission is performed from the data position where the error was detected. And a retransmission control unit 6 for performing the transmission.

  The data reading apparatus 1 described in the first to third embodiments performs data reading that does not include check data for each block while no error is detected. When an error is detected, in addition to the remaining data from the position where the error is detected, It is characterized by reading check data for each block.

  In the data reading device 1 described in the first to third embodiments, the optimum reception data for determining the optimum reception data length (response data length) from the history of error positions detected by the error detection / error position detection unit 7 is further provided. A length determination unit 9 is provided, and data communication with the IC tag 20 is performed using the reception data length (response data length) determined by the optimum reception data length determination unit 9.

  The data reading apparatus 1 described in the first to third embodiments includes a reception data correction unit 11 that receives error position information from the error detection / error position detection unit 7 and corrects reception data.

  The data reading device 1 described in the first to third embodiments is characterized in that when the received data correction unit 11 cannot correct the error, it retransmits the remaining data from the first detected error position.

  Although the first to third embodiments have been described above, two or more of these embodiments may be combined. Alternatively, one of these embodiments may be partially implemented. Or you may implement combining two or more embodiment among these partially.

  In the description of the first to third embodiments, the transmission control unit 2, the transmission unit 3, the reception processing unit 4, the reception control unit 5, and the retransmission control unit 6 in the data reading device 1 are independent of each other. Although it is configured as a functional block, it may be a single functional block. The reception processing unit 4 includes independent functional blocks including a reception unit 41, an error detection / error position detection unit 7, a reception buffer unit 8, a reception data correction unit 11, and an optimum reception data length determination unit 9. However, they may be combined into one functional block. Alternatively, all functional blocks may be independent functional blocks. Alternatively, these functional blocks may be configured in any other combination.

  The data reading device and the data reading method of the data reading device according to Embodiment 1 use hardware such as a processing device and a storage device, and information processing by software is specifically realized using hardware. Is. That is, the data reading device and the data reading method of the data reading device of the first embodiment described above are intended to realize the data reading device and the data reading method of the data reading device by the operation of hardware using the law of nature. It falls under technical creation using the laws of nature.

3 is a diagram illustrating an example of hardware resources of the data reading device 1 according to Embodiment 1. FIG. 1 is a diagram illustrating a configuration of a data reading device 1 of an RFID system 800 according to Embodiment 1. FIG. 3 is a configuration diagram of a memory 21 provided (held) in an IC tag 20 (an example of a communication device) according to Embodiment 1. FIG. 4 is a diagram showing a communication operation when the data reading device 1 in the first embodiment reads block data x including check data x from the IC tag 20 and no error is detected in the block data x. FIG. 6 is a diagram showing a format of received data D1 in the first embodiment. FIG. 4 is a diagram illustrating a communication operation when the data reading device 1 according to the first embodiment reads block data x including check data x from the IC tag 20 and detects an error in the block data x. FIG. FIG. 10 is a diagram showing a communication operation when the data reading device 1 in the second embodiment reads data x of a block x not including check data x from the IC tag 20 and no error is detected. FIG. 10 is a diagram illustrating a communication operation when the data reading device 1 according to the second embodiment reads data x of a block x that does not include check data x from the IC tag 20 and detects an error. 6 is a diagram illustrating a system configuration of an RFID system using a data reading device 1 according to Embodiment 3. FIG. FIG. 10 is a diagram illustrating a communication operation between the data reading device 1 and the IC tag 20 when an error is detected in the received data received from the IC tag 20 in the third embodiment. 6 is a diagram illustrating a normal frequency pattern of a bit string as a result of data encoding in wireless communication in the RFID system 800 according to Embodiment 1. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Data reader, 2 Transmission control part, 3 Transmission part, 4 Reception processing part, 5 Reception control part, 6 Retransmission control part, 7 Error detection / error position detection part, 8 Reception buffer part, 9 Optimum reception data length determination Part, 10a transmission antenna, 10b reception antenna, 11 reception data correction part, 20 IC tag, 21 memory, 41 reception part, 51 return preamble, 52 data part, 53, 53a, 53b, 53c CRC, 81 reception buffer, 500 computer , 800 RFID system, 901 display device, 902 keyboard, 903 mouse, 904 FDD, 905 CDD, 906 printer device, 907 scanner device, 910 system unit, 911 CPU, 912 bus, 913 ROM, 914 RAM, 915 communication board, 92 Magnetic disk drive, 921 OS, 922 Window system, 923 Program group, 924 File group, C1, C2 transmission command, D1, D2 received data.

Claims (7)

A data reading device that communicates with a communication device including a memory for storing data and reads data from the communication device,
A receiving unit for receiving the data from the communication device by a receiving device;
A predetermined error detection process for detecting an error in the data is performed on the data received by the receiving unit by the processing device. When an error is detected in the data, an error is detected in the data. An error detection / error position detection unit for specifying the error detection position by the processing device and outputting the error detection position;
Retransmission request that inputs the error detection position from the error detection / error position detection unit and requests the communication device to transmit partial data from the error detection position to the final position of the data in the data A retransmission control unit that generates a command by the processing device;
A data reading device comprising: a transmission unit that transmits a retransmission request command generated by the retransmission control unit to the communication device by a transmission device. The receiver is
From the communication device, the transmission unit receives the partial data transmitted as a response to the retransmission request command transmitted to the communication device,
The error detection / error position detection unit
When the predetermined error detection processing is performed on the partial data received by the receiving unit and no error is detected in the partial data, data from the start position of the data to the position before the error detection position 2. The data reading device according to claim 1, wherein data obtained by combining the partial data and the partial data is used as data read from the communication device. The receiver is
Receiving the data composed of first data and check data added after the first data and calculated for the validity check process of the first data;
The error detection / error position detection unit
An error detection in which an error is detected in the data when the predetermined error detection process is performed on the data composed of the first data and the check data and an error is detected in the data. Specify and output the position,
The retransmission control unit
The error detection position is input from the error detection / error position detection unit, and the communication device is requested to transmit partial data from the error detection position to the final position of the check data in the data. The data reading device according to claim 2, wherein the transmission request command is generated by a processing device. The error detection / error position detection unit
When an error is detected in the first data, an error detection position where the error is detected in the first data is specified, and an error detected as an error in the first data An error correction is performed on the data, and whether or not the first data including the corrected error data is valid data based on the check data included in the data received by the receiving unit. 4. The data according to claim 3, wherein the error check position of the first data is output when it is determined that the first data is not valid data by performing a sex check process by a processing device. Reading device. The error detection / error position detection unit
Based on the check data included in the partial data, a validity check process is performed by the processing device to determine whether the first data of the combined data is valid data, and the first data 5. The data reading device according to claim 3, wherein when the data is determined to be valid data, the combined data is data read from the communication device. 6. A data reading method of a data reading device that communicates with a communication device including a memory for storing data and reads data from the communication device,
A receiving step in which the receiving unit receives the data from the communication device by the receiving device;
When the error detection / error position detection unit performs a predetermined error detection process for detecting an error in the data received by the reception unit, and detects an error in the data. An error detection / error position detection step for specifying and outputting an error detection position where an error is detected in the data by the processing device;
The retransmission control unit inputs the error detection position from the error detection / error position detection unit, and transmits partial data from the error detection position in the data to the final position of the data to the communication device. A retransmission control step for generating a retransmission request command for requesting by the processing device;
A data reading method of a data reading device, characterized in that the transmission unit includes a transmission step of transmitting the retransmission request command generated by the retransmission control unit to the communication device by the transmission device. The receiving step is
The receiving unit receives the partial data transmitted from the communication device as a response to the retransmission request command transmitted by the transmitting unit to the communication device,
The error detection / error position detection step includes
When the predetermined error detection processing is performed on the partial data received by the receiving unit and no error is detected in the partial data, data from the start position of the data to the position before the error detection position 7. The data reading method of the data reading device according to claim 6, wherein data obtained by combining the partial data and the partial data is used as data read from the communication device.

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