Ahead-of-time scheduling of commands in RFID reader systems

• US 20070236335A1
• Filed: 08/23/2006
• Published: 10/11/2007
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Khwaja, Omar, Aiouaz, Ali, Ord, David
• Granted Patent: US 8,427,315 B2
• Time in Patent Office: Days
• US Class Current: 340/10.320
• 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
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals

Abstract

RFID reader systems, software and methods precompute one or more reader commands, before a tag actually responds to an earlier transmitted command. This way a system can result at a high data rate, while meeting specification requirements of responding within a preset time.

Claims

1. An operational processing block operable in conjunction with a radio frequency identification (RFID) reader system that has an antenna that is operable to exchange wireless waves with at least one RFID tag according to an air-interface communication protocol, the block operable to perform operations comprising:

transmitting a first reader command through the antenna in accordance with the protocol;

receiving a backscattered first tag response to the first reader command in accordance with the protocol;

generating a second reader command in accordance with the protocol, wherein generating commences before completely receiving the first tag response;

determining from the received first tag response whether the generated second reader command is to be transmitted; and

transmitting the generated second reader command responsive to the received first tag response only if it is so determined.

2. The operational processing block of claim 1, in which

the transmitted first reader command is part of a process for inventorying a group of tags, and

the generated second reader command continues the inventorying process.

3. The operational processing block of claim 2, in which the generated second reader command adjusts a parameter of the inventorying process.

4. The operational processing block of claim 1, in which

the protocol is the Gen2 Spec,

the transmitted first reader command comprises a Query command, and

the generated second reader command includes an Acknowledge command.

5. The operational processing block of claim 1, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is another QueryRep command.

6. The operational processing block of claim 1, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is a QueryAdj command.

7. The operational processing block of claim 1, in which

the protocol is the Gen2 spec,

the first reader command comprises an Acknowledge command, and

the generated second reader command is a QueryRep command.

8. The operational processing block of claim 1, in which

generating the second reader command commences before completing transmitting the first reader command.

9. The operational processing block of claim 1, in which

generating the second reader command commences before beginning transmitting the first reader command.

10. The operational processing block of claim 1, the operations further comprising:

looking up a stored parameter for the generated second reader command.

11. The operational processing block of claim 1, the operations further comprising:

storing the generated second reader command in a buffer.

12. The operational processing block of claim 11, in which

the second reader command is generated by processing at a first layer of the RFID reader system, and

the buffer is in a second layer of the RFID reader system.

13. The operational processing block of claim 11, in which

the second reader command is generated in a first layer of the RFID reader system.

the buffer is at the first layer, and

the second reader command is transferred to a second layer of the RFID reader system for being transmitted.

14. The operational processing block of claim 1, the operations further comprising:

error checking the received actual first tag response before transmitting the generated second reader command.

15. The operational processing block of claim 1, in which

a first tag response to the first reader command is anticipated according to the protocol, and

it is determined that the generated second reader command is to be transmitted depending on whether the received first tag response corresponds to the first anticipated tag response.

16. The operational processing block of claim 15, in which

the received first tag response corresponds to the first anticipated tag response if they match.

17. The operational processing block of claim 15, in which

the anticipated first tag response is a collision of responses from multiple tags.

18. The operational processing block of claim 15, the operations further comprising:

determining the anticipated first tag response; and

determining the second reader command in view of the anticipated first tag response.

19. The operational processing block of claim 18, in which

the first anticipated tag response is determined by looking up stored tag responses that are legitimate according to the protocol for responding to the first reader command.

20. The operational processing block of claim 15, in which

the second reader command is determined by looking up stored reader commands that are legitimate according to the protocol for responding to the first anticipated tag response.

21. The operational processing block of claim 20, the operations further comprising:

assembling reader commands that are legitimate according to the protocol for responding to the first anticipated tag response; and

selecting one of the assembled commands as the second reader command in view of the received first tag response.

22. The operational processing block of claim 15, in which

at least two anticipated first tag responses are legitimate according to the protocol for responding to the first reader command,

two reader commands are assembled that are desirable for responding to the anticipated first tag responses respectively, and

the transmitted second reader command is the one of the assembled two that corresponds to the one of the possible anticipated first tag responses that corresponds to the actual received first tag response.

23. The operational processing block of claim 22, the operations further comprising:

identifying which one of the two assembled reader commands is the one that corresponds to the one of the anticipated first tag responses that corresponds to the actual received first tag response.

24. The operational processing block of claim 22, in which

more than two anticipated first tag responses are legitimate according to the protocol, and

the operations further comprise:

generating additional second reader commands for responding to all the anticipated first tag responses respectively.

25. The operational processing block of claim 15, in which

an anticipated second tag response to the transmitted second reader command is legitimate according to the protocol, and

the operations further comprise:

generating a third reader command that is desirable for responding to the anticipated second tag response, in which generating commences before receiving an actual second tag response responsive to the transmitted second reader command;

receiving the actual second tag response; and

transmitting the generated third reader command, if the received actual second tag response corresponds to the second anticipated tag response.

26. The operational processing block of claim 25, the operations further comprising:

determining whether the received actual second tag response corresponds to the second anticipated tag response.

27. The operational processing block of claim 25, in which

generating the third reader command commences before transmitting the second reader command.

28. The operational processing block of claim 25, in which

generating the third reader command commences before transmitting the first reader command.

29. A radio frequency identification (RFID) reader system, comprising:

antenna means for exchange wireless waves with at least one RFID tag; and

operational processing block means operable to;

transmit a first reader command through the antenna in accordance with the protocol;

receive a backscattered first tag response to the first reader command in accordance with the protocol;

generate a second reader command in accordance with the protocol, wherein generating commences before completely receiving the first tag response;

determine from the received first tag response whether the generated second reader command is to be transmitted; and

transmit the generated second reader command responsive to the received first tag response only if it is so determined.

30. The device of claim 29, in which

the transmitted first reader command is part of a process for inventorying a group of tags, and

the generated second reader command continues the inventorying process.

31. The device of claim 30, in which

the generated second reader command adjusts a parameter of the inventorying process.

32. The device of claim 29, in which

the protocol is the Gen2 Spec,

the transmitted first reader command comprises a Query command, and

the generated second reader command includes an Acknowledge command.

33. The device of claim 29, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is another QueryRep command.

34. The device of claim 29, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is a QueryAdj command.

35. The device of claim 29, in which

the protocol is the Gen2 spec,

the first reader command comprises an Acknowledge command, and

the generated second reader command is a QueryRep command.

36. The device of claim 29, in which

generating the second reader command commences before completing transmitting the first reader command.

37. The device of claim 29, in which

generating the second reader command commences before beginning transmitting the first reader command.

38. The device of claim 29, in which the operational processing block further comprises means operable to:

store the generated second reader command in a buffer.

39. The device of claim 38, in which

the second reader command is generated by processing at a first layer of the RFID reader system, and

the buffer is in a second layer of the RFID reader system.

40. The device of claim 38, in which

the second reader command is generated in a first layer of the RFID reader system.

the buffer is at the first layer, and

the second reader command is transferred to a second layer of the RFID reader system for being transmitted.

41. The device of claim 29, in which the operational processing block further comprises means operable to:

error check the received actual first tag response before transmitting the generated second reader command.

42. The device of claim 29, in which

a first tag response to the first reader command is anticipated according to the protocol, and

it is determined that the generated second reader command is to be transmitted depending on whether the received first tag response corresponds to the first anticipated tag response.

43. The device of claim 42, in which

the received first tag response corresponds to the first anticipated tag response if they match.

44. The device of claim 42, in which the operational processing block further comprises means operable to:

determine the anticipated first tag response; and

determine the second reader command in view of the anticipated first tag response.

45. The device of claim 42, in which

the second reader command is determined by looking up stored reader commands that are legitimate according to the protocol for responding to the first anticipated tag response.

46. The device of claim 42, in which

at least two anticipated first tag responses are legitimate according to the protocol for responding to the first reader command,

two reader commands are assembled that are desirable for responding to the anticipated first tag responses respectively, and

the transmitted second reader command is the one of the assembled two that corresponds to the one of the possible anticipated first tag responses that corresponds to the actual received first tag response.

47. The device of claim 42, in which

an anticipated second tag response to the transmitted second reader command is legitimate according to the protocol, and

the operational processing block further comprises means operable to:

generate a third reader command that is desirable for responding to the anticipated second tag response, in which generating commences before receiving an actual second tag response responsive to the transmitted second reader command;

receive the actual second tag response; and

transmit the generated third reader command, if the received actual second tag response corresponds to the second anticipated tag response.

48. An article of manufacture having stored thereon instructions which, if executed by a radio frequency identification (RFID) reader system that uses an antenna operable to exchange wireless waves with at least one RFID tag according to an air-interface communication protocol, result in performing operations comprising:

transmitting a first reader command through the antenna in accordance with the protocol;

receiving a backscattered first tag response to the first reader command in accordance with the protocol;

generating a second reader command in accordance with the protocol, wherein generating commences before completely receiving the first tag response;

determining from the received first tag response whether the generated second reader command is to be transmitted; and

transmitting the generated second reader command responsive to the received first tag response only if it is so determined.

49. The article of manufacture of claim 48, in which

the transmitted first reader command is part of a process for inventorying a group of tags, and

the generated second reader command continues the inventorying process.

50. The article of manufacture of claim 49, in which

the generated second reader command adjusts a parameter of the inventorying process.

51. The article of manufacture of claim 48, in which

the protocol is the Gen2 Spec,

the transmitted first reader command comprises a Query command, and

the generated second reader command includes an Acknowledge command.

52. The article of manufacture of claim 48, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is another QueryRep command.

53. The article of manufacture of claim 48, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is a QueryAdj command.

54. The article of manufacture of claim 48, in which

the protocol is the Gen2 spec,

the first reader command comprises an Acknowledge command, and

the generated second reader command is a QueryRep command.

55. The article of manufacture of claim 48, in which

generating the second reader command commences before completing transmitting the first reader command.

56. The article of manufacture of claim 48, in which

generating the second reader command commences before beginning transmitting the first reader command.

57. The article of manufacture of claim 48, the operations further comprising:

looking up a stored parameter for the generated second reader command.

58. The article of manufacture of claim 48, the operations further comprising:

error checking the received actual first tag response before transmitting the generated second reader command.

59. The article of manufacture of claim 48, in which

a first tag response to the first reader command is anticipated according to the protocol, and

it is determined that the generated second reader command is to be transmitted depending on whether the received first tag response corresponds to the first anticipated tag response.

60. The article of manufacture of claim 59, in which

the received first tag response corresponds to the first anticipated tag response if they match.

61. The article of manufacture of claim 59, in which

the anticipated first tag response is a collision of responses from multiple tags.

62. The article of manufacture of claim 59, the operations further comprising:

determining the anticipated first tag response; and

determining the second reader command in view of the anticipated first tag response.

63. The article of manufacture of claim 62, in which

the first anticipated tag response is determined by looking up stored tag responses that are legitimate according to the protocol for responding to the first reader command.

64. The article of manufacture of claim 59, in which

the second reader command is determined by looking up stored reader commands that are legitimate according to the protocol for responding to the first anticipated tag response.

65. The article of manufacture of claim 64, the operations further comprising:

assembling reader commands that are legitimate according to the protocol for responding to the first anticipated tag response; and

selecting one of the assembled commands as the second reader command in view of the received first tag response.

66. The article of manufacture of claim 59, in which

at least two anticipated first tag responses are legitimate according to the protocol for responding to the first reader command,

two reader commands are assembled that are desirable for responding to the anticipated first tag responses respectively, and

the transmitted second reader command is the one of the assembled two that corresponds to the one of the possible anticipated first tag responses that corresponds to the actual received first tag response.

67. The article of manufacture of claim 66, the operations further comprising:

identifying which one of the two assembled reader commands is the one that corresponds to the one of the anticipated first tag responses that corresponds to the actual received first tag response.

68. The article of manufacture of claim 66, in which

more than two anticipated first tag responses are legitimate according to the protocol, and

the operations further comprise:

generating additional second reader commands for responding to all the anticipated first tag responses respectively.

69. The article of manufacture of claim 59, in which

an anticipated second tag response to the transmitted second reader command is legitimate according to the protocol, and

the operations further comprise:

generating a third reader command that is desirable for responding to the anticipated second tag response, in which generating commences before receiving an actual second tag response responsive to the transmitted second reader command;

receiving the actual second tag response; and

transmitting the generated third reader command, if the received actual second tag response corresponds to the second anticipated tag response.

70. The article of manufacture of claim 69, the operations further comprising:

determining whether the received actual second tag response corresponds to the second anticipated tag response.

71. The article of manufacture of claim 69, in which

generating the third reader command commences before transmitting the second reader command.

72. The article of manufacture of claim 69, in which

generating the third reader command commences before transmitting the first reader command.

73. A method for use by a radio frequency identification (RFID) reader system having an antenna to communicate with at least one RFID tag according to an air-interface communication protocol, comprising:

transmitting a first reader command through the antenna in accordance with the protocol;

receiving a backscattered first tag response to the first reader command in accordance with the protocol;

generating a second reader command in accordance with the protocol, wherein generating commences before completely receiving the first tag response;

determining from the received first tag response whether the generated second reader command is to be transmitted; and

transmitting the generated second reader command responsive to the received first tag response only if it is so determined.

74. The method of claim 73, in which

the transmitted first reader command is part of a process for inventorying a group of tags, and

the generated second reader command continues the inventorying process.

75. The method of claim 74, in which

the generated second reader command adjusts a parameter of the inventorying process.

76. The method of claim 73, in which

the protocol is the Gen2 Spec,

the transmitted first reader command comprises a Query command, and

the generated second reader command includes an Acknowledge command.

77. The method of claim 73, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is another QueryRep command.

78. The method of claim 73, in which

the protocol is the Gen2 spec,

the first reader command comprises a QueryRep command, and

the generated second reader command is a QueryAdj command.

79. The method of claim 73, in which

the protocol is the Gen2 spec,

the first reader command comprises an Acknowledge command, and

the generated second reader command is a QueryRep command.

80. The method of claim 73, in which

generating the second reader command commences before completing transmitting the first reader command.

81. The method of claim 73, in which

generating the second reader command commences before beginning transmitting the first reader command.

82. The method of claim 73, further comprising:

looking up a stored parameter for the generated second reader command.

83. The method of claim 73, further comprising:

storing the generated second reader command in a buffer.

84. The method of claim 83, in which

the second reader command is generated by processing at a first layer of the RFID reader system, and

the buffer is in a second layer of the RFID reader system.

85. The method of claim 83, in which

the second reader command is generated in a first layer of the RFID reader system.

the buffer is at the first layer, and

the second reader command is transferred to a second layer of the RFID reader system for being transmitted.

86. The method of claim 73, further comprising:

error checking the received actual first tag response before transmitting the generated second reader command.

87. The method of claim 73, in which

a first tag response to the first reader command is anticipated according to the protocol, and

it is determined that the generated second reader command is to be transmitted depending on whether the received first tag response corresponds to the first anticipated tag response.

88. The method of claim 87, in which

the received first tag response corresponds to the first anticipated tag response if they match.

89. The method of claim 87, further comprising:

determining the anticipated first tag response; and

determining the second reader command in view of the anticipated first tag response.

90. The method of claim 87, in which

the second reader command is determined by looking up stored reader commands that are legitimate according to the protocol for responding to the first anticipated tag response.

91. The method of claim 90, further comprising:

assembling reader commands that are legitimate according to the protocol for responding to the first anticipated tag response; and

selecting one of the assembled commands as the second reader command in view of the received first tag response.

92. The method of claim 87, in which

at least two anticipated first tag responses are legitimate according to the protocol for responding to the first reader command,

two reader commands are assembled that are desirable for responding to the anticipated first tag responses respectively, and

the transmitted second reader command is the one of the assembled two that corresponds to the one of the possible anticipated first tag responses that corresponds to the actual received first tag response.

93. The method of claim 92, further comprising:

identifying which one of the two assembled reader commands is the one that corresponds to the one of the anticipated first tag responses that corresponds to the actual received first tag response.

94. The method of claim 92,

in which more than two anticipated first tag responses are legitimate according to the protocol, and

further comprising:

generating additional second reader commands for responding to all the anticipated first tag responses respectively.