Method, apparatus and character set for encoding and decoding data characters in data carriers, such as RFID tags
First Claim
1. A method of encoding a string of data characters into a wireless, programmable RFID tag, comprising:
- determining a number of n-bit character codes corresponding to the data characters in the string, the character codes selected from an n-bit set character set that maps a plurality of human readable data characters to respective n-bit character codes, where a subset of the human readable data characters form an m-bit character set that maps the human readable data characters in the subset to respective m-bit character codes, where m is less than n;
parsing the number of n-bit character codes to separate the n-bit character codes corresponding to the data characters in the subset from the n-bit character codes corresponding to the data characters not in the subset;
converting the parsed n-bit character codes corresponding to the data characters in the subset into corresponding m-bit character codes, and outputting an output string of the m-bit character codes corresponding to data characters in the subset and the n-bit character codes corresponding to data characters not in the subset to program the RFID tag.
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Accused Products
Abstract
A method, apparatus and computer-readable character set encodes a string of n-bit character codes corresponding to the data characters from an n-bit set of data characters in a data carrier as a string of m-bit character codes, where m is less than n. A method, apparatus and character set, decodes a string of m-bit character codes corresponding to the data characters from an m-bit set of data characters from a data carrier as a string of n-bit character codes, where m is less than n. The n-bit character set contains character codes corresponding to operations and operating modes such as compression modes to efficiently encode and decode data. The n-bit character set further includes character codes that indicate the presence or absence of companion data carries, and that standing alone or in combination with a modifier character code can indicate an operation to be performed on data in the companion data carrier.
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Citations
28 Claims
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1. A method of encoding a string of data characters into a wireless, programmable RFID tag, comprising:
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determining a number of n-bit character codes corresponding to the data characters in the string, the character codes selected from an n-bit set character set that maps a plurality of human readable data characters to respective n-bit character codes, where a subset of the human readable data characters form an m-bit character set that maps the human readable data characters in the subset to respective m-bit character codes, where m is less than n;
parsing the number of n-bit character codes to separate the n-bit character codes corresponding to the data characters in the subset from the n-bit character codes corresponding to the data characters not in the subset;
converting the parsed n-bit character codes corresponding to the data characters in the subset into corresponding m-bit character codes, and outputting an output string of the m-bit character codes corresponding to data characters in the subset and the n-bit character codes corresponding to data characters not in the subset to program the RFID tag. - View Dependent Claims (2, 3, 4, 5, 6, 7)
inserting an m-bit character code proximate a string of n-bit character codes, the m-bit character code identifying a change from m-bit encoding to n-bit encoding.
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7. The method of claim 1, further comprising:
inserting an n-bit character code proximate a string of m-bit character codes, the n-bit character code identifying a change from n-bit encoding to m-bit encoding.
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8. A method of encoding a string of data characters into a memory, comprising:
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determining a number of n-bit character codes corresponding to the data characters in the string, the character codes selected from an n-bit set character set that maps a plurality of human readable data characters to respective n-bit character codes, where a subset of the human readable data characters form an m-bit character set that maps the human readable data characters in the subset to respective m-bit character codes, where m is less than n; and
for at least one of the data characters in the string, substituting the respective m-bit character code for the n-bit character code of at least one of the data characters that is in the subset. - View Dependent Claims (9, 10, 11)
operating an RF transmitter based on the string of character codes including the n-bit character codes substituted for the m-bit character codes to program the memory device.
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10. The method of claim 8, further comprising:
parsing the n-bit character codes to separate the n-bit character codes corresponding to characters in the m-bit set from the n-bit character codes of characters not in the m-bit character set.
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11. The method of claim 8 wherein the n is equal to 16 and m is equal to or less than 8.
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12. A method of decoding an input string of character codes from a wireless, programmable memory device, comprising:
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receiving the input string of n-bit and m-bit character codes selected from an n-bit character set that maps a plurality of human readable data characters to respective n-bit character codes, and an m-bit character set that maps a subset of the plurality of human readable data characters to respective m-bit character codes, where m is less than n;
parsing the input string of n-bit and m-bit character codes to separate the n-bit character codes from the m-bit character codes;
converting the m-bit character codes into corresponding n-bit character codes; and
assembling the n-bit character codes corresponding to the data characters in the input string that are contained in the subset and the n-bit character codes corresponding to the data characters in the input string that are not contained in the subset into an output string of n-bit character codes. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
transmitting an interrogation signal to the memory device;
receiving an RF response signal form the memory device; and
converting the RF response signal into the input string.
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14. The method of claim 12 wherein parsing the input string includes checking at least one bit position in the character codes for a predetermined value to identify the m-bit characters from the n-bit characters.
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15. The method of claim 12 wherein parsing the input string includes comparing the value of at least a portion of the character code to a predetermined value to identify the m-bit characters from the n-bit characters.
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16. The method of claim 12 wherein parsing the input string includes comparing the value of a functional character code to a predetermined value to identify the m-bit characters from the n-bit characters.
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17. The method of claim 12 wherein converting the m-bit character codes into corresponding n-bit character codes includes:
searching a conversion table of m-bit character codes to find the n-bit character code corresponding to a same human readable data character as the m-bit character code.
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18. The method of claim 12 wherein converting the m-bit character codes into corresponding n-bit character codes includes:
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searching a conversion table of m-bit character codes to find a portion of the n-bit character code corresponding to a same human readable data character as the m-bit character code; and
appending a base value to the portion of the corresponding n-bit character code to define the corresponding n-bit character code.
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19. The method of claim 12 wherein converting the m-bit character codes into corresponding n-bit character codes includes:
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searching a conversion table of m-bit character codes for an offset value corresponding to a same human readable data character as the m-bit character code; and
adding the offset value to a base value to define the corresponding n-bit character code.
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20. The method of claim 12 wherein converting the m-bit character codes into corresponding n-bit character codes includes:
calculating the corresponding n-bit character code from a formula.
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21. A method of decoding an input string of character codes from a wireless, programmable memory device, comprising:
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receiving the input string of n-bit and m-bit character codes selected from an n-bit character set that maps a plurality of human readable data characters to respective n-bit character codes and an m-bit character set that maps a subset of the plurality of human readable data characters to respective m-bit character codes, where m is less than n; and
for at least one of the m-bit character codes in the input string, substituting the n-bit character code from the n-bit character set that corresponds to the same human readable data character as the at least one m-bit character code. - View Dependent Claims (22, 23, 24, 25, 26)
interrogating the memory device with an RF interrogation signal;
receiving an RF response signal form the memory device; and
converting the RF response signal into the input string.
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23. The method of claim 21 wherein substituting the n-bit character code, includes:
searching a conversion table of m-bit character codes to find the n-bit character code corresponding to a same human readable data character as the m-bit character code.
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24. The method of claim 21 wherein substituting the n-bit character code, includes:
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searching a conversion table of m-bit character codes to find a portion of the n-bit character code corresponding to a same human readable data character as the m-bit character code; and
appending a base value to the portion of the corresponding n-bit character code to define the corresponding n-bit character code.
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25. The method of claim 21 wherein substituting the n-bit character code, includes:
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searching a conversion table of m-bit character codes for an offset value corresponding to a same human readable data character as the m-bit character code; and
adding the offset value to a base value to define the corresponding n-bit character code.
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26. The method of claim 21 wherein substituting the n-bit character code, includes:
calculating the corresponding n-bit character code from a formula.
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27. A computer readable medium whose contents cause a computer system to encode a string of data characters into a memory by:
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determining a number of n-bit character codes corresponding to the data characters in the string, the character codes selected from an n-bit set character set that maps a plurality of human readable data characters to respective n-bit character codes, where a subset of the human readable data characters from an m-bit character set that maps the human readable data characters in the subset to respective m-bit character codes, where m is less than n; and
for at least one of the data characters in the string, substituting the respective m-bit character code for the n-bit character code of at least one of the data characters that is in the subset.
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28. A computer readable medium whose contents cause a computer system to decode a string of data characters from a memory by:
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receiving the input string of n-bit and m-bit character codes selected from an n-bit character set that maps a plurality of human readable data characters to respective n-bit character codes, and an m-bit character set that maps a subset of the plurality of human readable data characters to respective m-bit character codes, where m is less than n; and
for at least one of the m-bit character codes in the input string, substituting the n-bit character code from the n-bit character set that corresponds to the same human readable data character as the at least one m-bit character code.
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Specification