Control device, control method, and control program for an RFID reader / writer.

Abstract

This invention provides a control device for an RFID reader / writer that can accurately detect and correct errors in the combination of TID and EPC. [Solution] An RFID reader / writer control device 1 controls the reading and writing of an RFID tag 30 by an RFID reader / writer 20, comprising: an error detection unit 6 that detects errors in the combination of a TID that is uniquely assigned to the RFID tag 30 and can only be read, and an EPC that can be read and written to the RFID tag 30, which is read from the RFID tag 30; and an error detection and correction code generation unit 12 that, when an error is detected by the error detection unit 6, attempts to correct the TID and EPC combination related to the error to determine the correct TID and EPC combination, and generates an error detection code and an error correction code as data combining the TID and EPC determined to be correct.

Description

Technical Field

[0001] The present disclosure relates to a control device, a control method, and a control program for an RFID reader / writer.

Background Art

[0002] In current RFID tags, when the code (first identification information) uniquely determined by the RFID vendor called TID read from the RFID tag, the EPC / UII (second identification information) including the vendor code and the product code, etc. are correct, it can be used as a valid RFID tag.

[0003] Patent Document 1 describes a configuration in which an error detection code called CRC16 is generally added to the EPC handled by an RFID tag to detect errors in the EPC. In addition, a configuration for correcting a 1-bit error by an ECC of a 1-bit error correction code is described for the TID used for identifying an RFID tag.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the prior art such as Patent Document 1, during a single RFID tag reading operation by a reader (RFID reader / writer) that reads information from an RFID tag, means for individually determining and correcting errors such as only the TID being incorrect, only the EPC / UII being incorrect, or both the TID and the EPC / UII being incorrect are provided. In the prior art, errors in the combination of the TID and the EPC are not determined and corrected. For this reason, it may not be possible to determine whether correct information is recorded in the RFID tag, and there may be a problem that it cannot be used as a valid RFID tag.

[0006] The purpose of this disclosure is to provide a control device, control method, and control program for an RFID reader / writer that can accurately determine and correct errors in the combination of first identification information such as TID and second identification information such as EPC. [Means for solving the problem]

[0007] A control device for an RFID reader / writer according to one aspect of an embodiment of the present invention is a control device for an RFID reader / writer that controls the reading and writing of an RFID tag by an RFID reader / writer, comprising: a control unit that reads from the RFID tag via the RFID reader / writer first identification information that is uniquely assigned to the RFID tag and can only be read, and second identification information that can be read and written to the RFID tag; an error detection unit that detects an error in the combination of the first identification information and the second identification information read by the control unit; a pattern counting unit that, when the error detection unit detects an error, counts the number of combination patterns of the first identification information and the second identification information and the number of pattern matches that match each pattern; and a control device that, based on the number of patterns and the number of pattern matches counted by the pattern counting unit, controls the combination of the first identification information and the second identification information. The system includes: a selection unit that selects a combination of first and second identification information; a correction unit that attempts to correct each character of the combination of first and second identification information that was not selected by the selection unit; a comparison unit that compares the combination of first and second identification information corrected by the correction unit with the combination of first and second identification information selected by the selection unit to see if they match; a determination unit that, if the comparison result by the comparison unit matches, adds up the number of pattern matches for the combination of first and second identification information selected by the selection unit, and then determines that the selected first and second identification information is correct based on the sum of the number of pattern matches for all patterns; and an error detection and correction code generation unit that generates an error detection code and an error correction code as data combining the first and second identification information that the determination unit has determined to be correct. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a control device, control method, and control program for an RFID reader / writer that can accurately determine and correct errors in the combination of first identification information such as TID and second identification information such as EPC. [Brief explanation of the drawing]

[0009] [Figure 1] Functional block diagram of the control device for the RFID reader / writer according to the first embodiment. [Figure 2] A schematic diagram illustrating the outline of the method for determining the correct combination of TID and EPC in the first embodiment. [Figure 3] Diagram showing the processing flow when reading a tag in the first embodiment. [Figure 4] Diagram showing the processing flow during tag writing in the first embodiment. [Figure 5] Flowchart of the method for determining the correct combination of TID and EPC in the first embodiment [Figure 6] Functional block diagram of the control device for the RFID reader / writer according to the second embodiment. [Figure 7] A schematic diagram illustrating the outline of the method for determining the correct combination of TID and EPC in the second embodiment. [Figure 8] Flowchart of the method for determining the correct combination of TID and EPC in the second embodiment [Figure 9] Hardware configuration diagram of the RFID reader / writer control unit. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.

[0011] [First Embodiment] The first embodiment will be described with reference to Figures 1 to 5.

[0012] Figure 1 is a functional block diagram of the control device 1 of the RFID reader / writer according to the first embodiment.

[0013] The RFID (Radio Frequency Identification) tag 30 is a recording medium for a system that wirelessly reads and rewrites data using radio waves (electromagnetic waves). The RFID tag 30 may also be called an IC tag, ID tag, RF tag, electronic tag, contactless tag, or wireless tag. Generally, the RFID tag 30 can record multiple types of information. In particular, the types of recorded information according to this embodiment include TID (Tag identification) and EPC (Electronic Product Code).

[0014] As shown in Figure 1, the RFID reader / writer 20 is a device that reads and writes data recorded on the RFID tag 30 via wireless communication.

[0015] Here, TID is information uniquely assigned to the RFID tag 30 by the tag manufacturer, and is an example of primary identification information that can only be read by devices such as the RFID reader / writer 20. EPC is a format for using GS1 identification codes with RFID, and is information based on standard identification codes defined by GS1, such as GTIN. EPC is an example of secondary identification information that can be read and written to the RFID tag 30 by devices such as the RFID reader / writer 20.

[0016] The control device 1 of the RFID reader / writer according to this embodiment (hereinafter sometimes simply referred to as "control device 1") controls the reading and writing of the RFID tag 30 by the RFID reader / writer 20. In particular, when reading from the RFID tag 30 via the RFID reader / writer 20, the control device 1 of this embodiment can determine and correct an error when the combination of the TID and EPC read from the tag is incorrect, and obtain correct RFID reading information. Further, an error correction code (TID, EPC error detection code, and TID, EPC error correction code) of information combining the TID and EPC can be generated and stored from the correct RFID reading information, and the error detection accuracy and correction ability can be improved.

[0017] Here, the case where "the combination of the TID and EPC is incorrect" can be considered in the following two cases.

[0018] The first case is when, for example, as in the combinations of the following (1) and (2), the same EPC is read in combination with different TIDs. The underlined part is the part that was misread. In this case, it is considered that there is an error in reading the TID of (1) or (2). (1) TID: E2806995200050163197B056 EPC: 006487D1400ABE00012C9110 (2) TID: E2806995200050163193B056 EPC: 006487D1400ABE00012C9110

[0019] The second case is when, for example, as in the combinations of the following (3) and (4), different EPCs are read in combination with the same TID. The underlined part is the part that was misread. In this case, it is considered that there is an error in reading the EPC of (3) or (4). (3) TID: E2806995200050163197B056 EPC: 006487D1400ABE00012C9110 (4)TID:E2806995200050163197B056 EPC:006487D1400ABE00012C9112

[0020] Next, the components of the control device 1 will be described with reference to Figure 1. As shown in Figure 1, the control device 1 comprises an RFID reader / writer control unit 2, a read buffer 3, a TID / EPC reading processing unit 4, a storage unit 5, an error detection unit 6, a pattern counting unit 7, a selection unit 8, a correction unit 9, a comparison unit 10, a determination unit 11, an error detection and correction code generation unit 12, a TID / EPC processing unit 13, an EPC writing processing unit 14, a write buffer 15, and a communication unit 16.

[0021] The RFID reader / writer control unit 2 controls the reading of information from the RFID tag 30 and the writing of information to the RFID tag 30 via the communication unit 16 and the RFID reader / writer 20. In particular, in this embodiment, the TID and EPC are read from the RFID tag 30 during read control, and the EPC is written to the RFID tag 30 during write control. Hereafter, the RFID reader / writer control unit 2 may also be simply referred to as "control unit 2".

[0022] The read buffer 3 temporarily stores the information read from the RFID tag 30 while the control unit 2 is controlling the reading process.

[0023] The TID, EPC reading processing unit 4 stores the TID and EPC dataset, which has been read by the control unit 2 from the RFID tag 30 and temporarily stored in the read buffer 3, into the storage unit 5.

[0024] The storage unit 5 temporarily stores the data sets of TID and EPC combinations read by the control unit 2. The storage unit 5 also stores the data sets of correct TID and EPC combinations, as well as the error detection and correction codes (TID, EPC error detection code and TID, EPC error correction code) corresponding to each data set.

[0025] The error detection unit 6 detects errors in the combination of TID and EPC read by the control unit 2.

[0026] In particular, in the first embodiment, the error detection unit 6 detects an error when it detects, based on the TID and EPC read by the control unit 2, that different TIDs contain the same EPC combination, or that the same TID contains different EPC combinations. The specific processing will be described later with reference to Figure 2 and other figures.

[0027] The pattern counting unit 7 counts the number of combination patterns of TID and EPC and the number of matching patterns for each pattern when an error is detected by the error detection unit 6.

[0028] The selection unit 8 selects a combination of TID and EPC based on the number of patterns and the number of matching patterns counted by the pattern counting unit.

[0029] The correction unit 9 attempts to correct each character of the TID and EPC combinations that were not selected by the selection unit 8.

[0030] The comparison unit 10 compares whether the combination of TID and EPC corrected by the correction unit 9 matches the combination of TID and EPC selected by the selection unit 8.

[0031] If the comparison results from the comparison unit 10 match, the determination unit 11 adds up the number of pattern matches for the TID and EPC combination selected by the selection unit 8, and then determines that the selected TID and EPC combination is correct based on the sum of the number of pattern matches for all patterns.

[0032] The error detection and correction code generation unit 12 generates an error detection code (TID, EPC error detection code) and an error correction code (TID, EPC error correction code) as data combining the TID and EPC that the determination unit 11 has determined to be correct.

[0033] When reading from the RFID tag 30, the TID,EPC processing unit 13 stores in the storage unit 5 a dataset consisting of the TID and EPC combination determined to be correct by the determination unit 11, and the error detection and correction code generated by the error detection and correction code generation unit 12 for this combination.

[0034] Furthermore, when writing to the RFID tag 30, the TID / EPC processing unit 13 generates a dataset of the TID of the tag to be written and the EPC to be written to this tag, and outputs it to the EPC writing processing unit 14. When writing to the RFID tag 30, the TID / EPC processing unit 13 outputs the dataset of the TID and EPC combination for writing to the error detection and correction code generation unit 12, which generates an error detection code based on the TID and EPC for writing.

[0035] When the EPC write processing unit 14 receives data sets for writing from the TID and EPC processing unit 13, it outputs these data sets to the write buffer 15.

[0036] The write buffer 15 temporarily stores the data set for writing received from the EPC writing processing unit 14. When writing to a tag, the control unit 2 controls the writing of the EPC stored in the write buffer 15 to the RFID tag 30 to be written.

[0037] The communication unit 16 transmits and receives information between the control unit 2 and the RFID reader / writer 20. The communication method used by the communication unit 16 can be general-purpose methods such as USB®, WiFi®, or Bluetooth®.

[0038] Figure 2 is a schematic diagram illustrating the method for determining the correct combination of TID and EPC in the first embodiment. As shown in Figure 2(A), the storage unit 5 is divided into a first storage area 51 and a second storage area 52. The first storage area 51 temporarily stores a data set of TID and EPC combinations read by the control unit 2. The second storage area 52 stores a data set of the correct combination of TID and EPC, and an error detection and correction code corresponding to each data set.

[0039] In the first embodiment, as shown in Figure 2(A), in the initial state, the second region 52 does not store a data set of the correct combination of TID and EPC.

[0040] Next, as shown in Figure 2(B1), the first region 51 stores a data set of TID and EPC combinations read by the control unit 2, and we consider the case where there are errors in these data sets. In the example in Figure 2(B1), two types of TIDs, T1 and T2, are used as examples, and two types of EPCs, E1 and E2. We assume that the pair of T1 and E1 and the pair of T2 and E2 are correct combinations.

[0041] In the example in Figure 2(B1), in addition to these correct combinations, the data set also includes incorrect combinations such as the pair T1 and E2, and the pair T2 and E1. In other words, in the example in Figure 2(B1), the error detection unit 6 can detect two errors 1 and 2, which correspond to the second case of "when the combination of TID and EPC is incorrect" as described above, namely, when different EPC combinations are read for the same TID, as in the combinations (3) and (4) above.

[0042] If such an error is detected, the correct combination is determined by a majority vote process, as described later, and the correct combinations, T1 and E1 and T2 and E2, are stored in the second area 52, as shown in Figure 2(C1). In addition, error detection and correction codes C1 and C2 corresponding to the T1 and E1 and T2 and E2 pairs are generated and stored in association with each pair.

[0043] Additionally, the pairs T1 and E2, and T2 and E1, which are determined to be incorrect combinations, are removed from the first region 51.

[0044] In the first embodiment, the first case of "when the combination of TID and EPC is incorrect," that is, the error corresponding to the case where the same EPC combination is read for different TIDs, as in the combinations of (1) and (2) above, can also be detected in the same way as in Figure 2(B1). In this case as well, similar to Figure 2(C1), only the correct combination of TID and EPC is stored in the second area 52 of the storage unit 5.

[0045] On the other hand, consider the case shown in Figure 2(B2) where the first area 51 stores a data set of TID and EPC combinations read by the control unit 2, and where there are no errors in this data set. In this case, since the data set stored in the first area 51 does not contain any incorrect combinations, the error detection unit 6 does not detect any errors. Therefore, the majority voting process described later to determine the correct combination is not performed, and as shown in Figure 2(C2), the T1 and E1 pair and the T2 and E2 pair in the first area 51 are stored as correct combinations in the second area 52. In addition, error detection correction codes C1 and C2 corresponding to the T1 and E1 pair and the T2 and E2 pair are also generated and stored in association with each pair.

[0046] As explained with reference to Figure 2, in the first embodiment, the error detection unit 6 can detect an error when it detects from the combination of TID and EPC read by the control unit 2 that different TIDs contain the same EPC combination, or the same TID contains different EPC combinations.

[0047] Figure 3 is a diagram showing the processing flow when reading a tag in the first embodiment. In Figure 3, the processing flow within the control device 1 when reading information from the RFID tag 30 is illustrated by thick arrows. In this case, first, the TID and EPC data group read from the RFID tag 30 is input to the control unit 2 via the RFID reader / writer 20 and the communication unit 16. The TID and EPC data input to the control unit 2 is temporarily stored in the first area 51 of the storage unit 5 via the read buffer 3 and the TID / EPC reading processing unit 4.

[0048] Next, the error detection unit 6 determines whether there are errors in the data stored in the first area 51 of the storage unit 5. If an error is detected, the pattern counting unit 7, selection unit 8, correction unit 9, comparison unit 10, and judgment unit 11 process in that order to determine the correct combination by majority vote and extract the correct TID and EPC combination. The TID and EPC data that is determined to be correct is output from the judgment unit 11 to the TID and EPC processing unit 13. This data is also output to the error detection and correction code generation unit 12, which generates an error detection and correction code based on the input TID and EPC and outputs it to the TID and EPC processing unit 13. The TID and EPC processing unit 13 associates the input correct TID and EPC data with the corresponding error detection and correction codes and stores them in the second area 52 of the storage unit 5.

[0049] Figure 4 shows the processing flow during tag writing in the first embodiment. As a prerequisite for write control, it is assumed that the tag reading process described with reference to Figure 3 has been performed and that the correct TID has been obtained.

[0050] Figure 4 illustrates the processing flow within the control device 1 when information is written from the control device 1 to the RFID tag 30, using thick arrows. In this case, the TID,EPC processing unit 13 determines the content of the EPC to be written to the RFID tag 30 that has a predetermined TID. It then outputs information including the determined EPC and the TID of the target tag to the error detection and correction code generation unit 12. The error detection and correction code generation unit 12 generates an error detection and correction code based on the TID and EPC pair input from the TID,EPC processing unit 13 and outputs it to the TID,EPC processing unit 13.

[0051] Next, the TID,EPC processing unit 13 outputs a dataset to the EPC writing processing unit 14 that includes the TID of the tag to be written, the EPC information to be written, and the error detection and correction code input from the error detection and correction code generation unit 12. The EPC writing processing unit 14 writes the EPC information specified by the TID,EPC processing unit 13 to the RFID tag 30 to be written, which has a predetermined TID, via the write buffer 15, control unit 2, communication unit 16, and RFID reader / writer 20.

[0052] Here, the control device 1 according to the first embodiment aims to accurately determine and correct errors in the combination of first identification information such as TID and second identification information such as EPC. The requirements for achieving this objective will be explained.

[0053] When reading information from RFID tags 30, it is necessary to accurately read the RFID's TID, as the only unique and reliable information is the vendor-specific TID.

[0054] Furthermore, in order to write the EPC to the RFID tag 30, the TID and EPC must be read by the RFID reader / writer 20 via the control unit 2 and the communication unit 16, and the RFID to be written to must be determined. At this time, it is essential that the TID of the RFID tag 30 to be written to is correct.

[0055] A blank RFID tag (i.e., an RFID tag 30 in its initial state at the time of manufacture) has a vendor-unique TID and an EPC that does not overlap with other RFID tags 30 written to it as initial values. Therefore, when multiple RFID tags 30 are read simultaneously by the RFID reader / writer 20, neither the TID nor the EPC can overlap.

[0056] However, it is possible to observe overlaps in the TID and EPC actually read by the RFID reader / writer 20. This is an unavoidable phenomenon that occurs because the RFID tag 30 communicates with the RFID reader / writer 20 using radio waves. In the control device 1 according to this embodiment, even when such a phenomenon occurs, the correct combination is determined by majority voting as shown below, thereby enabling the acquisition of an accurate TID.

[0057] Figure 5 is a flowchart of the method for determining the correct combination of TID and EPC in the first embodiment.

[0058] In steps S101 to S103, the communication unit 16, control unit 2, read buffer 3, and TID / EPC reading processing unit 4 store a dataset of multiple (in this case, N pairs) TID and EPC combinations simultaneously read from the RFID reader / writer 20 in the first area 51 of the storage unit 5. In other words, in the diagrams of Figures 2(B1) and (B2), the first area 51 stores a dataset of N pairs of TID and EPC combinations.

[0059] To make the processing of this control flow easier to understand, we will illustrate with an example where 2 to the power of 3 (N=8 pairs) of RFID tags 30 are read, and the TID and EPC patterns are read as follows. The combination of TID and EPC is denoted as "TID:EPC". TA, TB, and TC represent different types of TID, and EA and EB represent different types of EPC. The following explanation will refer to this example. ·TA:EA TB:EA TC:EB ·TA:EA ·TA:EA TA:EB ·TC:EA ·TC:EA

[0060] In step S104, the error detection unit 6 detects whether there are any identical EPC combinations for different TIDs, or any combinations of different EPCs for the same TID, among the N sets of TID and EPC combinations stored in the first area 51 of the storage unit 5.

[0061] If no error is detected by the error detection unit 6 (Yes in step S105), the process proceeds to step S106, where it is determined that all TID and EPC datasets stored in the first area 51 of the storage unit 5 are correct combinations. At this point, all TID and EPC combinations stored in the first area 51 are stored in the second area 52, and the control flow ends.

[0062] On the other hand, if an error is detected by the error detection unit 6 (No. in step S105), the process proceeds to step S107, where the correct combination is determined by majority voting.

[0063] In the eight example patterns mentioned above, the patterns "TA:EA", "TB:EA", and "TC:EA" are detected as errors indicating "the same EPC for different TIDs". Additionally, the patterns "TA:EA" and "TA:EB" are detected as errors indicating "different EPCs for the same TID".

[0064] In step S107, the pattern counting unit 7 counts the number of combination patterns of TID and EPC and the number of matching patterns classified into each pattern.

[0065] In the eight example patterns described above, the processing results of the pattern counting unit 7 are as follows. • Pattern 1 → TA:EA, Number of pattern matches → 3 • Pattern 2 → TB:EA, Number of pattern matches → 1 • Pattern 3 → TC:EA, Number of pattern matches → 2 • Pattern 4 → TA:EB, Number of pattern matches → 1 • Pattern 5 → TC:EB, Number of pattern matches → 1 In other words, the number of patterns is 5, and the number of matching patterns for each pattern is 3, 1, 2, 1, and 1.

[0066] In step S108, the selection unit 8 selects the TID and EPC combination pattern with the highest number of pattern matches in step S107, and the number of matches is obtained as M. The TID and EPC combination selected here becomes a candidate for the correct combination.

[0067] In the case of the eight example patterns described above, the processing result of selection unit 8 shows that the TID,EPC combination with the largest number of pattern matches is "TA:EA", and the number of pattern matches for this combination is M=3.

[0068] In step S108, the selection unit 8 may be configured to select the combination of TIC and EPC and the number of patterns M, where M1 / N and M2 / N are the largest, when N is the total number of matching patterns and M1, M2, etc., is the number of matching patterns for each pattern.

[0069] Furthermore, as a result of the processing in step S108, the first area 51 of the storage unit 5 will contain NM pairs of patterns that are different from the TID and EPC combination patterns that were selected as candidates for the correct combination in step S108. In step S109, the correction unit 9 attempts to correct the 2nd and 4th bits of the last 1 / 4 digits (6 digits if the data length is 24 digits) of the TID and EPC data length (for example, 24 digits) for these MN pair patterns that are different from the correct combinations. In other words, the correction unit 9 uses 1 / 4 of the number of information characters in each of the TID and EPC as characters to be corrected, and performs the correction by replacing the 0 and 1 in the 2nd and 4th bits of the characters to be corrected. Specifically, if the 2nd and 4th bits are 0, they are replaced with 1, and if they are 1, they are replaced with 0.

[0070] For example, consider the case where the 24-digit TID and 24-digit EPC are as follows: ·TID:E2806995200050163197B056 EPC:3D2DB3D312709A400F4B6C

[0071] In the above 24-digit TID and EPC, the binary representation of the last 6 characters, which corresponds to the last quarter of the digits, is as follows: • The last 6 characters of the TID: 1 0 0 1 0 1 1 1 1 0 1 1 0 0 0 0 0 1 0 1 0 1 1 0 • The last 6 letters of EPC: 0 0 0 0 1 1 1 1 0 1 0 0 1 0 1 1 0 1 1 0 1 1 0 0

[0072] For the TID and EPC combinations not selected in selection unit 8 (the four patterns in the eight example patterns above: "TB:EA", "TC:EA", "TA:EB", and "TC:EB"), the 2nd and 4th bits of the last six characters are sequentially replaced, generating 24 possible combinations of TID and EPC (6 characters x 4 patterns).

[0073] In steps S110 to S112, the comparison unit 10 compares the corrected TID and EPC combination in step S109 with the TID and EPC pattern selected as a candidate for the correct combination by the selection unit 8 in step S108 (S110). If the two match (Yes in step S111), the number of matches is added to the number of matching patterns M (S112).

[0074] In the eight example patterns described above, the generated TID and EPC combinations are compared with the TID and EPC combination pattern "TA:EA" selected in selection unit 8. If the generated TID and EPC combination matches the selected TID and EPC combination, M = M + 1 is added to the number of matching patterns.

[0075] On the other hand, if the corrected TID and EPC combination in step S109 does not match the TID and EPC pattern selected as a candidate for the correct combination by the selection unit 8 in step S108 (No. in step S111), the number of matching patterns M in step S112 is not incremented and the process proceeds to step S113.

[0076] The processing in steps S110 to S112 is performed for all TID and EPC patterns of NM pairs that were not selected as correct combination candidates by the selection unit 8 in step S108. In other words, it is repeated until NM times are reached, which corresponds to the number of patterns not selected by the selection unit 8 (No. in step S113).

[0077] After steps S110 to S112 are repeated NM times (Yes in step S113), the process proceeds to step S114. If, for example, P pairs match as a result of steps S110 to S112, the comparison unit 10 adds P to the number of matching patterns M of the correct combination candidates. At this point, the new number of matching patterns M after step S113 is M + P (M = M + P).

[0078] In step S114, the determination unit 11 calculates M / N using the M candidate sets of correct combinations of TID and EPC and the N sets read by the RFID reader / writer 20 and stored in the first area 51 of the storage unit 5, and determines whether the condition M / N > 0.5 is satisfied.

[0079] If M / N > 0.5 (Yes in step S114), the process proceeds to step S115, where the determination unit 11 determines that the correct combination candidate of M sets selected by the selection unit 8 (and further incremented if there is a match in the comparison unit 10) is the correct combination of TID and EPC. In other words, the determination unit 11 calculates M / N using the number of patterns M obtained from the comparison by the comparison unit 10 and the total number of matching patterns N obtained by the selection unit 8, and determines that the combination of TID and EPC is correct if M / N is 0.5 or greater.

[0080] At this time, the TID / EPC processing unit 13 selects the RFID tag 30 with the correct TID as the tag to which the EPC will be written, and prepares the EPC to be written to this tag. This TID and EPC dataset is transmitted from the TID / EPC processing unit 13 to the RFID reader / writer 20 via the EPC writing processing unit 14, the control unit 2, and the communication unit 16. The RFID reader / writer 20 then writes the EPC specified by the TID / EPC processing unit 13 to the RFID tag 30 to be written.

[0081] In the eight example patterns described above, if the comparison of the corrected patterns by the correction unit 9 results in two combinations matching the pattern selected by the selection unit 8, and M=5, then M / N, or 5 / (2 to the power of 3) = 5 / 8 > 0.5. Therefore, in the eight example patterns described above, step S114 determines that the TID,EPC combination pattern selected by the selection unit 8 is the correct TID,EPC.

[0082] On the other hand, for example, if the comparison of the corrected patterns by the correction unit 9 results in only one combination matching the pattern selected by the selection unit 8, and M=4, then M / N becomes 4 / 8=0.5, and it is determined that there is no correct TID,EPC pattern.

[0083] In step S115, the TID,EPC processing unit 13 outputs the TID of the tag to be written and the prepared EPC information to the error detection and correction code generation unit 12. In step S116, the error detection and correction code generation unit 12 generates an error detection and correction code based on the TID and EPC input from the TID,EPC processing unit 13 in step S115. The error detection and correction code generation unit 12 generates a TID,EPC error detection code using a well-known method such as a block code or hash function, treating the TID and EPC as a single data, and also generates a TID,EPC error correction code using a well-known method such as a block code or convolution code. The error detection and correction code generation unit 12 stores the generated TID,EPC error detection code and TID,EPC error correction code in the second area 52 of the storage unit 5 via the TID,EPC processing unit 13. The information stored in the storage unit 5 may be stored in or provided to an external device via the communication unit 16 or the like.

[0084] [Second Embodiment] The first embodiment will be described with reference to Figures 6 to 8.

[0085] Figure 6 is a functional block diagram of the control device 1A of the RFID reader / writer according to the second embodiment. As shown in Figure 6, the configuration of the second embodiment differs from the first embodiment in that the correct combination of TID and EPC, and the correct data of the error detection and correction code are provided to the storage unit 5 and the error detection unit 6 via the communication unit 16 from an external device 40 such as an external storage device or network.

[0086] Figure 7 is a schematic diagram illustrating the method for determining the correct combination of TID and EPC in the second embodiment. In the second embodiment, as shown in Figure 7(A), in the initial state, the second area 52 of the storage unit 5 already stores data sets of the correct combinations of TID and EPC "T1, E1" and "T2, E2", and the correct error detection and correction code data C1 and C2 corresponding to each combination. This data is provided to the control device 1A in advance from the external device 40, as described above.

[0087] Next, as shown in Figure 7(B1), consider the case where a data set of TID and EPC combinations read by the control unit 2 is stored in the first area 51 of the storage unit 5, and where there are errors in these data sets. In this case, similar to Figure 2(B1), the correct combinations of T1 and E1 and T2 and E2, and the incorrect combinations of T1 and E2 and T2 and E1 are stored in the first area 51.

[0088] In the second embodiment, in the state shown in Figure 7(B1), the error detection unit 6 compares the data sets in the first area 51 and the second area 52 of the storage unit 5. A read error is detected if there is a data set in the first area 51 that is not included in the second area 52. In the example of Figure 7(B1), the second case of "when the combination of TID and EPC is incorrect" described above, that is, the incorrect combination of the T1 and E2 pair and the T2 and E1 pair, as in the combinations of (3) and (4) described above, is stored in the first area 51, so the error detection unit 6 can detect these data sets as errors.

[0089] If such an error is detected, the correct combination is determined by majority voting as described in the first embodiment, and as shown in Figure 7(C1), the correct combinations, the pair T1 and E1 and the pair T2 and E2, are stored in the second area 52. In addition, error detection and correction codes C1 and C2 corresponding to the pair T1 and E1 and the pair T2 and E2 are generated and stored in association with each pair.

[0090] Additionally, the pairs T1 and E2, and T2 and E1, which are determined to be incorrect combinations, are removed from the first region 51.

[0091] In the second embodiment, the first case of "when the combination of TID and EPC is incorrect," that is, the error that occurs when the same combination of EPC is read for different TIDs, as in the combinations of (1) and (2) above, can also be detected in the same way as in Figure 7(B1). In this case as well, similar to Figure 7(C1), only the correct combination of TID and EPC is stored in the second area 52 of the storage unit 5.

[0092] On the other hand, consider the case shown in Figure 7(B2) where the first area 51 stores a data set of TID and EPC combinations read by the control unit 2, and where there are no errors in this data set. In this case, the data set stored in the first area 51 is included in the data set stored in the second area 52, so no error is detected by the error detection unit 6. For this reason, the majority vote process for determining the correct combination, as described in the first embodiment, is not performed, and as shown in Figure 7(C2), the T1 and E1 pair and the T2 and E2 pair in the first area 51 are stored in the second area 52 as correct combinations. In other words, the contents of the second area 52 are not changed.

[0093] As explained with reference to Figure 7, in the second embodiment, the error detection unit 6 can detect an error when the combination of TID and EPC stored in the first area 51 of the storage unit 5 does not match a given correct combination of TID and EPC stored in the second area 52, based on the TID and EPC read by the control unit 2.

[0094] Figure 8 is a flowchart of the method for determining the correct combination of TID and EPC in the second embodiment. The processing in steps S201 to S203 and S205 to S217 is the same as steps S101 to S103 and S104 to S117 of the first embodiment, which were explained with reference to Figure 5, so their explanation is omitted.

[0095] In step S205, the error detection unit 6 detects whether there is a correct TID and EPC combination in the positive data memory (i.e., the second area 52) among the N sets of TID and EPC combinations stored in the first area 51 of the storage unit 5. If a data set stored in the first area 51 does not contain a correct combination in the positive data memory, the error detection unit 6 detects an error.

[0096] Figure 9 is a hardware configuration diagram of the RFID reader / writer control devices 1 and 1A. As shown in Figure 9, the control devices 1 and 1A according to the first and second embodiments described above can be physically configured as a computer system including a processor 101 which includes a CPU (Central Processing Unit) and GPU, RAM (Random Access Memory) 102 and ROM (Read Only Memory) 103 which are main memory devices, input devices 104 which include a keyboard and mouse, output devices 105 which include a display, a communication module 106 which is a data transmission / reception device such as a network card, and auxiliary storage devices 107 which include a hard disk. The functions of the control devices 1 and 1A described above are realized by loading predetermined computer software (RFID reader / writer control program) onto the hardware such as the processor 101 and RAM 102, thereby operating the communication module 106, input devices 104 and output devices 105 under the control of the processor 101, and reading and writing data to RAM 102 and auxiliary storage devices 107.

[0097] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise.

[0098] In the above embodiment, a configuration is shown that uses TID as "first identification information that is uniquely assigned to the RFID tag and can only be read," but other information such as UID (Unique Identification) may be used instead of TID if it is similar information. [Explanation of Symbols]

[0099] 1. Control device for RFID reader / writer 2 RFID Reader / Writer Control Unit (Control Unit) 6. Error detection unit 7 Pattern counting unit 8. Selection Section 9. Correction Unit 10 Comparison Section 11 Judgment Department 12 Error detection and correction code generation unit 20 RFID Reader / Writer 30 RFID tags

Claims

1. A control device for an RFID reader / writer that controls the reading and writing of RFID tags by an RFID reader / writer, A control unit reads from the RFID tag via the RFID reader / writer a first identification information unique to the RFID tag and read-only, and a second identification information that can be read and written to the RFID tag. An error detection unit that detects an error in the combination of the first identification information and the second identification information read by the control unit, When the error detection unit detects the error, a pattern counting unit counts the number of combination patterns of the first identification information and the second identification information and the number of matching patterns that match each pattern. A selection unit selects a combination of the first identification information and the second identification information based on the number of patterns and the number of matching patterns counted by the pattern counting unit. A correction unit attempts to correct each character of the combination of the first identification information and the second identification information that was not selected by the selection unit, A comparison unit compares whether the combination of the first identification information and the second identification information after correction by the correction unit matches the combination of the first identification information and the second identification information selected by the selection unit. If the comparison results from the comparison unit match, the selection unit adds up the number of matching patterns for the combination of the first identification information and the second identification information selected by the selection unit, and then the determination unit determines that the selected first identification information and the second identification information are correct based on the sum of the matching patterns for all patterns. An error detection and correction code generation unit generates an error detection code and an error correction code as data combining the first identification information and the second identification information that the determination unit has determined to be correct. A control device for an RFID reader / writer, equipped with the following features.

2. The error detection unit, The control unit detects the error when it detects from the combination of the first identification information and the second identification information that different first identification information contains the same combination of second identification information, or the same first identification information contains different combinations of second identification information. A control device for an RFID reader / writer according to claim 1.

3. The error detection unit, The control unit detects the error when the combination of the first identification information and the second identification information read by the control unit does not match a given correct combination of the first identification information and the second identification information. A control device for an RFID reader / writer according to claim 1.

4. The selection unit selects the combination of the first identification information and the second identification information, and the number of patterns M, where M1 / N, M2 / N... is the pattern with the largest total number of matching patterns N and the number of matching patterns for each pattern M1, M2, ... A control device for an RFID reader / writer according to claim 1.

5. The correction unit selects 1 / 4 of the number of characters in the first identification information and the second identification information as characters to be corrected, and performs the correction by replacing the 2nd and 4th bits (0 and 1) of the characters to be corrected. The control device for the RFID reader / writer according to claim 4.

6. The comparison unit compares the combination of the first identification information and the second identification information corrected by the correction unit with the combination of the first identification information and the second identification information selected by the selection unit, and if they match, adds the number of matches to the number of patterns M selected by the selection unit. The control device for the RFID reader / writer according to claim 5.

7. The determination unit calculates M / N using the number of patterns M obtained from the comparison by the comparison unit and the total number of matching patterns N obtained by the selection unit, and determines that the combination of the first identification information and the second identification information is correct if M / N is 0.5 or more. The control device for the RFID reader / writer according to claim 6.

8. The error detection and correction code generation unit generates an error detection code using a block code, a hash function, and an error correction code using a block code and a convolution code, using the first identification information and the second identification information as a single data. A control device for an RFID reader / writer according to claim 1.

9. The first identification information includes a TID or a UID, The second identification information includes EPC, A control device for an RFID reader / writer according to claim 1.

10. A method for controlling an RFID reader / writer to control the reading and writing of RFID tags by the RFID reader / writer, A reading step in which, via the RFID reader / writer, a first identification information unique to the RFID tag and read-only, and a second identification information that can be read and written to the RFID tag are read from the RFID tag. An error detection step for detecting an error in the combination of the first identification information and the second identification information read in the reading step, If the error is detected in the error detection step, a pattern counting step is performed to count the number of combination patterns of the first identification information and the second identification information and the number of pattern matches that match each pattern. A selection step in which a combination of the first identification information and the second identification information is selected based on the number of patterns and the number of matching patterns counted in the pattern counting step, A correction step is performed to attempt to correct each character of the combination of the first identification information and the second identification information that was not selected in the selection step, A comparison step to compare whether the corrected combination of the first identification information and the second identification information in the correction step matches the combination of the first identification information and the second identification information selected in the selection step, If the comparison results in the comparison step match, the number of pattern matches for the combination of the first identification information and the second identification information selected in the selection step is added, and then the selected first identification information and the second identification information are judged to be correct based on the sum of the number of pattern matches for all patterns. An error detection and correction code generation step generates an error detection code and an error correction code as data combining the first identification information and the second identification information that were determined to be correct in the judgment step, A method for controlling an RFID reader / writer, including [the specified method].

11. An RFID reader / writer control program that controls the reading and writing of RFID tags by an RFID reader / writer, A reading function that reads from the RFID tag via the RFID reader / writer a first identification information that is uniquely assigned to the RFID tag and is read-only, and a second identification information that is readable and writable to the RFID tag. An error detection function that detects errors in the combination of the first identification information and the second identification information read by the reading function, When the error is detected by the error detection function, a pattern counting function counts the number of combination patterns of the first identification information and the second identification information and the number of matching patterns for each pattern. A selection function that selects a combination of the first identification information and the second identification information based on the number of patterns and the number of matching patterns counted by the pattern counting function, A correction function that attempts to correct each character of the combination of the first identification information and the second identification information that was not selected by the selection function, A comparison function that compares whether the combination of the first identification information and the second identification information after correction by the correction function matches the combination of the first identification information and the second identification information selected by the selection function, When the comparison results from the comparison function match, the number of matching patterns for the combination of the first and second identification information selected by the selection function is added, and then the selected first and second identification information is judged to be correct based on the sum of the number of matching patterns for all patterns. An error detection and correction code generation function generates an error detection code and an error correction code as data combining the first identification information and the second identification information that are determined to be correct by the aforementioned judgment function, A control program for an RFID reader / writer to enable this functionality on a computer.

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