RFID readers and tags transmitting and receiving waveform segment with ending-triggering transition

• US 7,187,290 B2
• Filed: 02/02/2006
• Issued: 03/06/2007
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Hyde, John D., Diorio, Christopher J.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US11/347,734
• Publication Number:
  US 20070024446A1
• Time in Patent Office: 397 Days
• Field of Search: 340/572.1, 340/572.4, 340/505, 340/5.23, 340/5.25, 340/5.6, 340/10.1, 340/10.3, 340/10.51, 340/1.52, 235/432, 235/472.01, 375/336, 704/260, 382/239, 396/550, 396/551, 700/203
• US Class Current: 340/572.1
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10297 arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092 cryptographic protocols H04L9/00; network security protocols H04L63/00; real-time communication protocols in data switching networks H04L65/00; network protocols for data switching network services H04L67/00

Abstract

RFID readers exchange information with RFID tags. The information is encoded for transmission and decoded upon reception. Encoding is in binary bits, which are in turn encoded in waveform segments. The last transmitted waveform incorporates an ending-triggering transition, and terminates in a preset manner with respect to when the ending-triggering transition occurs. Parsing while decoding can happen by waiting for the ending-triggering transition, and then waiting according to the preset manner. This way there is no ambiguity in the ending of the waveform, and no End Frame is necessary.

Claims

1. An RFID reader configured to:

encode information in terms of RFID symbols;

encode the RFID symbols into successive waveform segments that individually correspond to the RFID symbols, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition; and

transmit a signal wave having a waveform made from the segments.

2. The reader of claim 1, further configured to:

transmit a preamble to the signal wave.

3. The reader of claim 1, further configured to:

transmit a wave that encodes neither information, nor that the last segment has been transmitted.

4. The reader of claim 1, wherein

the preset manner is that the last segment terminates a preset number of additional transitions after the ending-triggering transition occurs.

5. The reader of claim 1, wherein

the preset manner is that the last segment terminates upon the occurrence of the ending-triggering transition.

6. The reader of claim 1, wherein

the preset manner is that the last segment terminates a preset time interval after the transition occurs.

7. The reader of claim 6, wherein

the interval is a preset fraction of a symbol period.

8. The reader of claim 1, wherein

the segments belong in a segment set, and

at least some but not all of the segments in the set incorporate the ending-triggering transition.

9. The reader of claim 1, wherein

one of the symbols is encoded by one of a plurality of different waveform segments depending on whether there is a next symbol.

10. The reader of claim 1, wherein

the RFID symbols are encoded so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

11. The reader of claim 1, wherein

the segments belong in a segment set, and

all of the segments in the set incorporate the ending-triggering transition.

12. The reader of claim 1, wherein

the RFID symbols are encoded so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

13. An RFID reader configured to:

receive a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition;

receive a wave, after reception of the last segment, that encodes neither information nor that the last segment has been received;

parse the waveform segments according to the preset manner and the ending-triggering transition;

decode RFID symbols from the parsed waveform segments; and

decode information from the decoded RFID symbols.

14. The reader of claim 13, further configured to:

receive a preamble to the signal wave.

15. The reader of claim 13, wherein

the preset manner is that the last segment terminates a preset number of additional transitions after the ending-triggering transition occurs.

16. The reader of claim 13, wherein

the preset manner is that the last segment terminates upon the occurrence of the ending-triggering transition.

17. The reader of claim 13, wherein

the preset manner is that the last segment terminates a preset time interval after the transition occurs.

18. The reader of claim 17, wherein

the interval is a preset fraction of a symbol period.

19. The reader of claim 13, wherein

the segments belong in a segment set, and

at least some but not all of the segments in the set incorporate the ending-triggering transition.

20. The reader of claim 13, wherein

one of the symbols is decoded from different waveform segments depending on whether there is a next symbol.

21. The reader of claim 13, wherein

the RFID symbols are decoded so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

22. The reader of claim 13, wherein

the segments belong in a segment set, and

all of the segments in the set incorporate the ending-triggering transition.

23. The reader of claim 13, wherein

the RFID symbols are decoded so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

24. An RFID tag configured to:

encode information in terms of RFID symbols;

encode the RFID symbols into successive waveform segments that individually correspond to the RFID symbols, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition; and

transmit a signal wave having a waveform made from the segments.

25. The tag of claim 24, further configured to:

transmit a preamble to the signal wave.

26. The tag of claim 24, further configured to:

transmit a wave that encodes neither information, nor that the last segment has been transmitted.

27. The tag of claim 24, wherein

the preset manner is that the last segment terminates a preset number of additional transitions after the ending-triggering transition occurs.

28. The tag of claim 24, wherein

the preset manner is that the last segment terminates upon the occurrence of the ending-triggering transition.

29. The tag of claim 24, wherein

the preset manner is that the last segment terminates a preset time interval after the transition occurs.

30. The tag of claim 29, wherein

the interval is a preset fraction of a symbol period.

31. The tag of claim 24, wherein

the segments belong in a segment set, and

at least some but not all of the segments in the set incorporate the ending-triggering transition.

32. The tag of claim 24, wherein

one of the symbols is encoded by one of a plurality of different waveform segments depending on whether there is a next symbol.

33. The tag of claim 24, wherein

the RFID symbols are encoded so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

34. The tag of claim 24, wherein

the segments belong in a segment set, and

all of the segments in the set incorporate the ending-triggering transition.

35. The tag of claim 24, wherein

the RFID symbols are encoded so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

36. An RFID tag configured to:

receive a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition;

after receiving the last segment, receive a wave that encodes neither information nor that the last segment has been received;

parse the waveform segments according to the preset manner and the ending-triggering transition;

decode RFID symbols from the parsed waveform segments; and

decode information from the decoded RFID symbols.

37. The tag of claim 36, further configured to:

receive a preamble to the signal wave.

38. The tag of claim 36, wherein

the preset manner is that the last segment terminates a preset number of additional transitions after the ending-triggering transition occurs.

39. The tag of claim 36;

wherein

the preset manner is that the last segment terminates upon the occurrence of the ending-triggering transition.

40. The tag of claim 36, wherein

the preset manner is that the last segment terminates a preset time interval after the transition occurs.

41. The tag of claim 40, wherein

the interval is a preset fraction of a symbol period.

42. The tag of claim 36, wherein

the segments belong in a segment set, and

at least some but not all of the segments in the set incorporate the ending-triggering transition.

43. The tag of claim 36, wherein

one of the symbols is decoded from different waveform segments depending on whether there is a next symbol.

44. The tag of claim 36, wherein

the RFID symbols are decoded so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

45. The tag of claim 36, wherein

the segments belong in a segment set, and

all of the segments in the set incorporate the ending-triggering transition.

46. The tag of claim 36, wherein

the RFID symbols are decoded so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

47. A device comprising:

means for encoding information in terms of RFID symbols;

means for encoding the RFID symbols into successive waveform segments that individually correspond to the RFID symbols, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition; and

means for transmitting a signal wave having a waveform made from the segments, wherein

the RFID symbols are encoded so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

48. A device comprising:

means for encoding information in terms of RFID symbols;

means for encoding the RFID symbols into successive waveform segments that individually correspond to the RFID symbols, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition; and

means for transmitting a signal wave having a waveform made from the segments, wherein

the RFID symbols are encoded so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

49. A method comprising:

encoding information in terms of RFID symbols;

encoding the RFID symbols into successive waveform segments that individually correspond to the RFID symbols, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition; and

transmitting a signal wave having a waveform made from the segments,

wherein said encoding the RFID symbols takes place so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

50. A method comprising:

encoding information in terms of RFID symbols;

encoding the RFID symbols into successive waveform segments that individually correspond to the RFID symbols, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition; and

transmitting a signal wave having a waveform made from the segments,

wherein said encoding the RFID symbols takes place so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

51. A device comprising:

means for receiving a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition;

means for, after receiving the last segment, receiving a wave that encodes neither information nor that the last segment has been received;

means for parsing the waveform segments according to the preset manner and the ending-triggering transition;

means for decoding RFID symbols from the parsed waveform segments; and

means for decoding information from the decoded RFID symbols,

wherein said means for decoding RFID symbols is configured to operate so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

52. A device comprising:

means for receiving a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition;

means for after receiving the last segment, receiving a wave that encodes neither information nor that the last segment has been received;

means for parsing the waveform segments according to the preset manner and the ending-triggering transition;

means for decoding RFID symbols from the parsed waveform segments; and

means for decoding information from the decoded RFID symbols,

wherein said means for decoding RFID symbols is configured to operate operates so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

53. A method comprising:

receiving a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition;

after receiving the last segment, receiving a wave that encodes neither information nor that the last segment has been received;

parsing the waveform segments according to the preset manner and the ending-triggering transition;

decoding RFID symbols from the parsed waveform segments; and

decoding information from the decoded RFID symbols,

wherein said decoding RFID symbols takes place so that the RFID symbol for “

0”

is encoded 10-0X0-01-1X1-10 and the RFID symbol for “

1”

is encoded (a) 01-1X1-10 if there is a next symbol and that next symbol is a “

0” and

(b) 01-1X1-10-0X0-01 otherwise.

54. A method comprising:

receiving a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition;

after receiving the last segment, receiving a wave that encodes neither information nor that the last segment has been received;

parsing the waveform segments according to the preset manner and the ending-triggering transition;

decoding RFID symbols from the parsed waveform segments; and

decoding information from the decoded RFID symbols,

wherein said decoding RFID symbols takes place so that the RFID symbol for “

0”

is encoded 1S1-10-0X0-01 and the RFID symbol for “

1”

is encoded 1L1-10-0X0-01.

55. An RFID tag comprising:

an antenna system adapted to receive a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition, and after receiving the last segment, to receive a wave that encodes neither information nor that the last segment has been received; and

circuitry adapted to;

parse the waveform segments according to the preset manner and the ending-triggering transition;

decode RFID symbols from the parsed waveform segments; and

decode information from the decoded RFID symbols.

56. The tag of claim 55, wherein

the antenna system is further adapted to receive a preamble to the signal wave.

57. The tag of claim 55, wherein

the antenna system is further adapted to then receive a wave that encodes neither information, nor that the last segment has been transmitted.

58. The tag of claim 55, wherein

the preset manner is that the last segment terminates a preset number of additional transitions after the ending-triggering transition occurs.

59. The tag of claim 55, wherein

the preset manner is that the last segment terminates upon the occurrence of the ending-triggering transition.

60. The tag of claim 55, wherein

the preset manner is that the last segment terminates a preset time interval after the transition occurs.

61. The tag of claim 60, wherein

the interval is a preset fraction of a symbol period.

62. The tag of claim 55, wherein

the preset manner is that the last segment terminates when the transition occurs.

63. The tag of claim 55, wherein the circuitry is further adapted so that

one of the symbols is decoded by one of a plurality of different waveform segments depending on whether there is a next symbol.

64. The tag of claim 55, wherein

the segments belong in a segment set, and

all of the segments in the set incorporate the ending-triggering transition.

65. An integrated circuit (IC) for an RFID tag that has an antenna system adapted to receive a signal wave having a waveform made from successive waveform segments, the last one of the segments incorporating an ending-triggering transition and terminating in a preset manner with respect to the occurrence of the ending-triggering transition, and after receiving the last segment, to receive a wave that encodes neither information nor that the last segment has been received, the IC comprising:

circuitry adapted to;

parse the waveform segments according to the preset manner and the ending-triggering transition;

decode RFID symbols from the parsed waveform segments; and

decode information from the decoded RFID symbols.

66. The IC of claim 65, wherein

the antenna system is further adapted to receive a preamble to the signal wave.

67. The IC of claim 65, wherein

the antenna system is further adapted to then receive a wave that encodes neither information, nor that the last segment has been transmitted.

68. The IC of claim 65, wherein

the preset manner is that the last segment terminates a preset number of additional transitions after the ending-triggering transition occurs.

69. The IC of claim 65, wherein

the preset manner is that the last segment terminates upon the occurrence of the ending-triggering transition.

70. The IC of claim 65, wherein

the preset manner is that the last segment terminates a preset time interval after the transition occurs.

71. The IC of claim 65, wherein

the interval is a preset fraction of a symbol period.

72. The IC of claim 65, wherein

the preset manner is that the last segment terminates when the transition occurs.

73. The IC of claim 65, wherein the circuitry is further adapted so that

one of the symbols is decoded by one of a plurality of different waveform segments depending on whether there is a next symbol.

74. The IC of claim 65, wherein

the segments belong in a segment set, and

all of the segments in the set incorporate the ending-triggering transition.